notification module

Backend/ERPCore.Tests/ERPCore.Tests.csproj

@@ -0,0 +1,26 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="10.0.9" />
+    <PackageReference Include="coverlet.collector" Version="6.0.4" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageReference Include="xunit" Version="2.9.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.4" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\ERPCore\ERPCore.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+</Project>

Backend/ERPCore.Tests/NotificationConfigServiceTests.cs

@@ -0,0 +1,152 @@
+using ERPCore.Domain.Entities;
+using ERPCore.Domain.Notifications;
+using ERPCore.Repositories;
+using ERPCore.Services;
+using ERPCore.System.Errors;
+using ERPCore.Tests.TestSupport;
+using Microsoft.EntityFrameworkCore;
+
+namespace ERPCore.Tests;
+
+public class NotificationConfigServiceTests
+{
+    [Fact]
+    public async Task GetAsync_MergesSavedValuesWithDiscoveredModules()
+    {
+        var dbName = Guid.NewGuid().ToString("N");
+        await using var db = NotificationConfigTestSupport.CreateContext(dbName);
+        await NotificationConfigTestSupport.SeedAsync(db, new[]
+        {
+            new NotificationConfigModule
+            {
+                ModuleKey = "sale.create",
+                EmailEnabled = true,
+                SmsEnabled = false,
+                InAppEnabled = true
+            }
+        });
+
+        var service = CreateService(db);
+
+        var result = await service.GetAsync();
+
+        Assert.Equal(7u, result.RowVersion);
+        Assert.Contains(result.Value.Modules, m => m.ModuleKey == "sale.create" && m.EmailEnabled && !m.SmsEnabled && m.InAppEnabled);
+        Assert.Contains(result.Value.Modules, m => m.ModuleKey == "grn.confirmed" && !m.EmailEnabled && !m.SmsEnabled && !m.InAppEnabled);
+    }
+
+    [Fact]
+    public async Task UpdateAsync_PersistsEmptyAndMultiChannelSelections()
+    {
+        var dbName = Guid.NewGuid().ToString("N");
+        await using var db = NotificationConfigTestSupport.CreateContext(dbName);
+        await NotificationConfigTestSupport.SeedAsync(db);
+
+        var service = CreateService(db);
+        var catalog = new NotificationModuleCatalog();
+        var request = new ERPCore.Dtos.Notifications.UpdateNotificationConfigRequest
+        {
+            Modules = catalog.GetAll().Select((module, index) => new ERPCore.Dtos.Notifications.UpdateNotificationModuleRequest
+            {
+                ModuleKey = module.Key,
+                EmailEnabled = index == 0,
+                SmsEnabled = index == 1,
+                InAppEnabled = index == 1
+            }).ToList()
+        };
+
+        var updated = await service.UpdateAsync(request, 7);
+
+        Assert.Equal(7u, updated.RowVersion);
+        Assert.Contains(updated.Value.Modules, m => m.ModuleKey == catalog.GetAll()[0].Key && m.EmailEnabled && !m.SmsEnabled && !m.InAppEnabled);
+        Assert.Contains(updated.Value.Modules, m => m.ModuleKey == catalog.GetAll()[1].Key && !m.EmailEnabled && m.SmsEnabled && m.InAppEnabled);
+
+        await using var verifyDb = NotificationConfigTestSupport.CreateContext(dbName);
+        var persisted = await verifyDb.NotificationConfigModules.AsNoTracking().ToListAsync();
+        Assert.Contains(persisted, m => m.ModuleKey == catalog.GetAll()[0].Key && m.EmailEnabled && !m.SmsEnabled && !m.InAppEnabled);
+        Assert.Contains(persisted, m => m.ModuleKey == catalog.GetAll()[1].Key && !m.EmailEnabled && m.SmsEnabled && m.InAppEnabled);
+    }
+
+    [Fact]
+    public async Task ResolveEnabledChannelsAsync_ReturnsEmptyWhenNothingEnabled()
+    {
+        var dbName = Guid.NewGuid().ToString("N");
+        await using var db = NotificationConfigTestSupport.CreateContext(dbName);
+        await NotificationConfigTestSupport.SeedAsync(db, new[]
+        {
+            new NotificationConfigModule
+            {
+                ModuleKey = "sale.create",
+                EmailEnabled = false,
+                SmsEnabled = false,
+                InAppEnabled = false
+            }
+        });
+
+        var service = CreateService(db);
+
+        var channels = await service.ResolveEnabledChannelsAsync("sale.create");
+
+        Assert.Empty(channels);
+    }
+
+    [Fact]
+    public async Task ResolveEnabledChannelsAsync_ReturnsMultipleChannels()
+    {
+        var dbName = Guid.NewGuid().ToString("N");
+        await using var db = NotificationConfigTestSupport.CreateContext(dbName);
+        await NotificationConfigTestSupport.SeedAsync(db, new[]
+        {
+            new NotificationConfigModule
+            {
+                ModuleKey = "sale.create",
+                EmailEnabled = true,
+                SmsEnabled = true,
+                InAppEnabled = false
+            }
+        });
+
+        var service = CreateService(db);
+
+        var channels = await service.ResolveEnabledChannelsAsync("sale.create");
+
+        Assert.Equal(new[] { NotificationChannel.Email, NotificationChannel.Sms }, channels);
+    }
+
+    [Fact]
+    public async Task UpdateAsync_MapsConcurrencyFailuresToDomainException()
+    {
+        var dbName = Guid.NewGuid().ToString("N");
+        await using var db = NotificationConfigTestSupport.CreateContext(dbName);
+        await NotificationConfigTestSupport.SeedAsync(db);
+
+        var service = CreateService(db, new ThrowingUnitOfWork());
+        var catalog = new NotificationModuleCatalog();
+        var request = new ERPCore.Dtos.Notifications.UpdateNotificationConfigRequest
+        {
+            Modules = catalog.GetAll().Select(module => new ERPCore.Dtos.Notifications.UpdateNotificationModuleRequest
+            {
+                ModuleKey = module.Key,
+                EmailEnabled = false,
+                SmsEnabled = false,
+                InAppEnabled = false
+            }).ToList()
+        };
+
+        var ex = await Assert.ThrowsAsync<DomainException>(() => service.UpdateAsync(request, 7));
+        Assert.Equal(ErrorCodes.ConcurrencyConflict, ex.Code);
+        Assert.Equal(412, ex.StatusCode);
+    }
+
+    private static NotificationConfigService CreateService(ERPCore.Infra.Persistence.ErpDbContext db, ERPCore.Infra.UoW.IUnitOfWork? uow = null)
+    {
+        var configRepo = new Repository<NotificationConfig>(db);
+        var moduleRepo = new Repository<NotificationConfigModule>(db);
+        return new NotificationConfigService(
+            configRepo,
+            moduleRepo,
+            new NotificationModuleCatalog(),
+            new TestCurrentUser(),
+            uow ?? new ERPCore.Infra.UoW.UnitOfWork(db));
+    }
+}

Backend/ERPCore.Tests/NotificationModuleCatalogTests.cs

@@ -0,0 +1,17 @@
+using ERPCore.Services;
+
+namespace ERPCore.Tests;
+
+public class NotificationModuleCatalogTests
+{
+    [Fact]
+    public void GetAll_ReturnsStableUniqueModuleKeys()
+    {
+        var catalog = new NotificationModuleCatalog();
+
+        Assert.NotEmpty(catalog.GetAll());
+        Assert.Contains(catalog.GetAll(), m => m.Key == "sale.create");
+        Assert.Contains(catalog.GetAll(), m => m.Key == "grn.confirmed");
+        Assert.Equal(catalog.GetAll().Count, catalog.GetAll().Select(m => m.Key).Distinct(StringComparer.OrdinalIgnoreCase).Count());
+    }
+}

Backend/ERPCore.Tests/TestSupport/NotificationConfigTestSupport.cs

@@ -0,0 +1,70 @@
+using ERPCore.Domain.Entities;
+using ERPCore.Infra.Auth;
+using ERPCore.Infra.Persistence;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Storage;
+
+namespace ERPCore.Tests.TestSupport;
+
+internal sealed class TestCurrentUser : ICurrentUser
+{
+    public string UserId => "system";
+    public int AuditUserId => User.SystemUserId;
+    public bool IsAuthenticated => false;
+}
+
+internal sealed class ThrowingUnitOfWork : ERPCore.Infra.UoW.IUnitOfWork
+{
+    public Task<int> SaveChangesAsync(CancellationToken ct = default)
+        => throw new DbUpdateConcurrencyException("Test concurrency conflict.");
+
+    public Task ExecuteInTransactionAsync(Func<CancellationToken, Task> action, CancellationToken ct = default)
+        => throw new NotSupportedException();
+
+    public Task<T> ExecuteInTransactionAsync<T>(Func<CancellationToken, Task<T>> action, CancellationToken ct = default)
+        => throw new NotSupportedException();
+}
+
+internal static class NotificationConfigTestSupport
+{
+    private static readonly InMemoryDatabaseRoot Root = new();
+
+    public static ErpDbContext CreateContext(string name)
+    {
+        var options = new DbContextOptionsBuilder<ErpDbContext>()
+            .UseInMemoryDatabase(name, Root)
+            .Options;
+
+        return new ErpDbContext(options, new TestCurrentUser());
+    }
+
+    public static async Task SeedAsync(ErpDbContext db, IEnumerable<NotificationConfigModule>? modules = null)
+    {
+        db.Users.Add(new User
+        {
+            UserId = User.SystemUserId,
+            Username = "system",
+            DisplayName = "System"
+        });
+
+        var config = new NotificationConfig
+        {
+            NotificationConfigId = NotificationConfig.SingletonId,
+            UpdatedBy = User.SystemUserId,
+            UpdatedAt = DateTime.UtcNow,
+            RowVersion = 7,
+        };
+
+        if (modules is not null)
+        {
+            foreach (var module in modules)
+            {
+                module.NotificationConfigId = NotificationConfig.SingletonId;
+                config.Modules.Add(module);
+            }
+        }
+
+        db.NotificationConfig.Add(config);
+        await db.SaveChangesAsync();
+    }
+}

Backend/ERPCore/Controllers/NotificationConfigController.cs

@@ -0,0 +1,34 @@
+using ERPCore.Dtos.Notifications;
+using ERPCore.Services.Interfaces;
+using Microsoft.AspNetCore.Mvc;
+
+namespace ERPCore.Controllers;
+
+[Route("api/v1/notification-config")]
+public sealed class NotificationConfigController : ApiControllerBase
+{
+    private readonly INotificationConfigService _config;
+
+    public NotificationConfigController(INotificationConfigService config) => _config = config;
+
+    [HttpGet]
+    [ProducesResponseType(typeof(NotificationConfigDto), StatusCodes.Status200OK)]
+    public async Task<ActionResult<NotificationConfigDto>> Get(CancellationToken ct)
+    {
+        var result = await _config.GetAsync(ct);
+        SetETag(result.RowVersion);
+        return Ok(result.Value);
+    }
+
+    [HttpPut]
+    [ProducesResponseType(typeof(NotificationConfigDto), StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status400BadRequest)]
+    [ProducesResponseType(StatusCodes.Status412PreconditionFailed)]
+    public async Task<ActionResult<NotificationConfigDto>> Update([FromBody] UpdateNotificationConfigRequest request, CancellationToken ct)
+    {
+        var expected = RequireIfMatch();
+        var result = await _config.UpdateAsync(request, expected, ct);
+        SetETag(result.RowVersion);
+        return Ok(result.Value);
+    }
+}

Backend/ERPCore/Domain/Entities/NotificationConfig.cs

@@ -0,0 +1,19 @@
+namespace ERPCore.Domain.Entities;
+
+/// <summary>
+/// Notification configuration (new settings module) - singleton root row.
+/// </summary>
+public class NotificationConfig
+{
+    public const int SingletonId = 1;
+
+    public int NotificationConfigId { get; set; }
+
+    public DateTime? UpdatedAt { get; set; }
+    public int? UpdatedBy { get; set; }
+    public User? UpdatedByUser { get; set; }
+
+    public uint RowVersion { get; set; }
+
+    public ICollection<NotificationConfigModule> Modules { get; set; } = new List<NotificationConfigModule>();
+}

Backend/ERPCore/Domain/Entities/NotificationConfigModule.cs

@@ -0,0 +1,14 @@
+namespace ERPCore.Domain.Entities;
+
+public class NotificationConfigModule
+{
+    public int NotificationConfigModuleId { get; set; }
+
+    public int NotificationConfigId { get; set; }
+    public NotificationConfig? NotificationConfig { get; set; }
+
+    public string ModuleKey { get; set; } = string.Empty;
+    public bool EmailEnabled { get; set; }
+    public bool SmsEnabled { get; set; }
+    public bool InAppEnabled { get; set; }
+}

Backend/ERPCore/Domain/Entities/ProductConfig.cs

@@ -1,22 +1,24 @@
 namespace ERPCore.Domain.Entities;
 
 /// <summary>
-/// Product configuration (FR-MD-11) — a <b>singleton row</b> (single-tenant, docs/00-CORE §1)
+/// Product configuration (FR-MD-11) - a singleton row (single-tenant, docs/00-CORE §1)
 /// gating optional product master-data features.
 /// <para>
 /// <see cref="SubcategoriesEnabled"/> and <see cref="BrandsEnabled"/> are enforced
 /// server-side: an Item write carrying a subcategory/brand while the flag is off is
-/// rejected with <c>CONFIG_DISABLED</c>. <see cref="ItemTypesEnabled"/> is
-/// <b>advisory only</b> — items carry no item-type reference (see <see cref="ItemType"/>),
-/// so there is nothing on a write to reject; the frontend honours it by hiding the
-/// builder's type section. Reads are never gated, so existing data stays visible after a
-/// flag is switched off.
+/// rejected with <c>CONFIG_DISABLED</c>. <see cref="ItemTypesEnabled"/> is advisory only
+/// - items carry no item-type reference (see <see cref="ItemType"/>), so there is nothing
+/// on a write to reject; the frontend honours it by hiding the variant builder.
+/// <see cref="SellingPricesEnabled"/>, <see cref="SerialNumbersEnabled"/>,
+/// <see cref="BatchListsEnabled"/> and <see cref="WarrantyPeriodsEnabled"/> are enforced
+/// on item writes and drive the create/edit screens. Reads are never gated, so existing
+/// data stays visible after a flag is switched off.
 /// </para>
 /// Model: docs/10-BACKEND-PHASE1.md Part C.1.
 /// </summary>
 public class ProductConfig
 {
-    /// <summary>Always 1 — the singleton row's id.</summary>
+    /// <summary>Always 1 - the singleton row's id.</summary>
     public const int SingletonId = 1;
 
     public int ConfigId { get; set; }
@@ -24,6 +26,10 @@ public class ProductConfig
     public bool SubcategoriesEnabled { get; set; } = true;
     public bool BrandsEnabled { get; set; } = true;
     public bool ItemTypesEnabled { get; set; } = true;
+    public bool SellingPricesEnabled { get; set; } = true;
+    public bool SerialNumbersEnabled { get; set; } = true;
+    public bool BatchListsEnabled { get; set; } = true;
+    public bool WarrantyPeriodsEnabled { get; set; } = true;
 
     public DateTime? UpdatedAt { get; set; }
 

Backend/ERPCore/Domain/Notifications/Modules/NotificationModules.cs

@@ -0,0 +1,34 @@
+namespace ERPCore.Domain.Notifications.Modules;
+
+[NotificationModule("sale.create", "Sale Created", "Raised when a sales document is created.", 10)]
+public sealed class SaleCreateNotificationModule;
+
+[NotificationModule("sale.posted", "Sale Posted", "Raised when a sales document is posted.", 20)]
+public sealed class SalePostedNotificationModule;
+
+[NotificationModule("grn.created", "GRN Created", "Raised when a goods receipt note is created.", 30)]
+public sealed class GrnCreatedNotificationModule;
+
+[NotificationModule("grn.confirmed", "GRN Confirmed", "Raised when a goods receipt note is confirmed.", 40)]
+public sealed class GrnConfirmedNotificationModule;
+
+[NotificationModule("purchase.order.created", "Purchase Order Created", "Raised when a purchase order is created.", 50)]
+public sealed class PurchaseOrderCreatedNotificationModule;
+
+[NotificationModule("purchase.order.approved", "Purchase Order Approved", "Raised when a purchase order is approved.", 60)]
+public sealed class PurchaseOrderApprovedNotificationModule;
+
+[NotificationModule("purchase.return.created", "Purchase Return Created", "Raised when a purchase return is created.", 70)]
+public sealed class PurchaseReturnCreatedNotificationModule;
+
+[NotificationModule("stock.adjustment.created", "Stock Adjustment Created", "Raised when a stock adjustment is created.", 80)]
+public sealed class StockAdjustmentCreatedNotificationModule;
+
+[NotificationModule("stock.transfer.created", "Stock Transfer Created", "Raised when a stock transfer is created.", 90)]
+public sealed class StockTransferCreatedNotificationModule;
+
+[NotificationModule("item.created", "Item Created", "Raised when an item master record is created.", 100)]
+public sealed class ItemCreatedNotificationModule;
+
+[NotificationModule("item.updated", "Item Updated", "Raised when an item master record is updated.", 110)]
+public sealed class ItemUpdatedNotificationModule;

Backend/ERPCore/Domain/Notifications/NotificationChannel.cs

@@ -0,0 +1,8 @@
+namespace ERPCore.Domain.Notifications;
+
+public enum NotificationChannel
+{
+    Email,
+    Sms,
+    InApp
+}

Backend/ERPCore/Domain/Notifications/NotificationModuleAttribute.cs

@@ -0,0 +1,18 @@
+namespace ERPCore.Domain.Notifications;
+
+[AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
+public sealed class NotificationModuleAttribute : Attribute
+{
+    public string Key { get; }
+    public string Label { get; }
+    public string Description { get; }
+    public int SortOrder { get; }
+
+    public NotificationModuleAttribute(string key, string label, string description, int sortOrder)
+    {
+        Key = key;
+        Label = label;
+        Description = description;
+        SortOrder = sortOrder;
+    }
+}

Backend/ERPCore/Domain/Notifications/NotificationModuleDefinition.cs

@@ -0,0 +1,7 @@
+namespace ERPCore.Domain.Notifications;
+
+public sealed record NotificationModuleDefinition(
+    string Key,
+    string Label,
+    string Description,
+    int SortOrder);

Backend/ERPCore/Dtos/Config/ProductConfigDtos.cs

@@ -4,10 +4,14 @@ namespace ERPCore.Dtos.Config;
 
 /// <summary>
 /// Product configuration resource (docs/11-BACKEND-PHASE1.md §2.8). Singleton.
-/// <see cref="ItemTypesEnabled"/> is advisory (frontend-honoured) — see the entity docs.
+/// <see cref="ItemTypesEnabled"/> is advisory (frontend-honoured) - see the entity docs.
+/// <see cref="SellingPricesEnabled"/>, <see cref="SerialNumbersEnabled"/>,
+/// <see cref="BatchListsEnabled"/> and <see cref="WarrantyPeriodsEnabled"/> are enforced
+/// when items are written.
 /// </summary>
 public sealed record ProductConfigDto(
     bool SubcategoriesEnabled, bool BrandsEnabled, bool ItemTypesEnabled,
+    bool SellingPricesEnabled, bool SerialNumbersEnabled, bool BatchListsEnabled, bool WarrantyPeriodsEnabled,
     DateTime? UpdatedAt, int? UpdatedBy);
 
 /// <summary>
@@ -15,8 +19,8 @@ public sealed record ProductConfigDto(
 /// <para>
 /// The flags are <see cref="bool"/>? deliberately: <c>[Required]</c> on a non-nullable bool
 /// is a no-op (it always has a value), so a body of <c>{}</c> would bind every flag to
-/// <c>false</c> and silently switch all three features off. Nullable makes the requirement
-/// actually bind — an omitted flag is a 400, not an accidental disable.
+/// <c>false</c> and silently switch everything off. Nullable makes the requirement actually
+/// bind - an omitted flag is a 400, not an accidental disable.
 /// </para>
 /// </summary>
 public sealed class UpdateProductConfigRequest
@@ -24,4 +28,8 @@ public sealed class UpdateProductConfigRequest
     [Required] public bool? SubcategoriesEnabled { get; set; }
     [Required] public bool? BrandsEnabled { get; set; }
     [Required] public bool? ItemTypesEnabled { get; set; }
+    [Required] public bool? SellingPricesEnabled { get; set; }
+    [Required] public bool? SerialNumbersEnabled { get; set; }
+    [Required] public bool? BatchListsEnabled { get; set; }
+    [Required] public bool? WarrantyPeriodsEnabled { get; set; }
 }

Backend/ERPCore/Dtos/Notifications/NotificationConfigDtos.cs

@@ -0,0 +1,29 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace ERPCore.Dtos.Notifications;
+
+public sealed record NotificationModuleConfigDto(
+    string ModuleKey,
+    string Label,
+    string Description,
+    bool EmailEnabled,
+    bool SmsEnabled,
+    bool InAppEnabled);
+
+public sealed record NotificationConfigDto(
+    IReadOnlyList<NotificationModuleConfigDto> Modules,
+    DateTime? UpdatedAt,
+    int? UpdatedBy);
+
+public sealed class UpdateNotificationModuleRequest
+{
+    [Required, StringLength(100)] public string ModuleKey { get; set; } = string.Empty;
+    [Required] public bool? EmailEnabled { get; set; }
+    [Required] public bool? SmsEnabled { get; set; }
+    [Required] public bool? InAppEnabled { get; set; }
+}
+
+public sealed class UpdateNotificationConfigRequest
+{
+    [Required, MinLength(0)] public List<UpdateNotificationModuleRequest> Modules { get; set; } = new();
+}

Backend/ERPCore/Infra/Persistence/Configurations/NotificationConfigConfiguration.cs

@@ -0,0 +1,29 @@
+using ERPCore.Domain.Entities;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+
+namespace ERPCore.Infra.Persistence.Configurations;
+
+public sealed class NotificationConfigConfiguration : IEntityTypeConfiguration<NotificationConfig>
+{
+    public void Configure(EntityTypeBuilder<NotificationConfig> builder)
+    {
+        builder.ToTable("notification_config", t =>
+            t.HasCheckConstraint("ck_notification_config_singleton", $"\"NotificationConfigId\" = {NotificationConfig.SingletonId}"));
+
+        builder.HasKey(c => c.NotificationConfigId);
+        builder.Property(c => c.NotificationConfigId).ValueGeneratedNever();
+
+        builder.Property(c => c.RowVersion).IsRowVersion();
+
+        builder.HasMany(c => c.Modules)
+            .WithOne(m => m.NotificationConfig)
+            .HasForeignKey(m => m.NotificationConfigId)
+            .OnDelete(DeleteBehavior.Cascade);
+
+        builder.HasOne(c => c.UpdatedByUser)
+            .WithMany()
+            .HasForeignKey(c => c.UpdatedBy)
+            .OnDelete(DeleteBehavior.Restrict);
+    }
+}

Backend/ERPCore/Infra/Persistence/Configurations/NotificationConfigModuleConfiguration.cs

@@ -0,0 +1,21 @@
+using ERPCore.Domain.Entities;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+
+namespace ERPCore.Infra.Persistence.Configurations;
+
+public sealed class NotificationConfigModuleConfiguration : IEntityTypeConfiguration<NotificationConfigModule>
+{
+    public void Configure(EntityTypeBuilder<NotificationConfigModule> builder)
+    {
+        builder.ToTable("notification_config_modules");
+        builder.HasKey(m => m.NotificationConfigModuleId);
+
+        builder.Property(m => m.ModuleKey).IsRequired().HasMaxLength(100);
+        builder.HasIndex(m => m.ModuleKey).IsUnique();
+
+        builder.Property(m => m.EmailEnabled).IsRequired().HasDefaultValue(false);
+        builder.Property(m => m.SmsEnabled).IsRequired().HasDefaultValue(false);
+        builder.Property(m => m.InAppEnabled).IsRequired().HasDefaultValue(false);
+    }
+}

Backend/ERPCore/Infra/Persistence/Configurations/ProductConfigConfiguration.cs

@@ -25,6 +25,10 @@ public sealed class ProductConfigConfiguration : IEntityTypeConfiguration<Produc
         builder.Property(c => c.SubcategoriesEnabled).IsRequired().HasDefaultValue(true);
         builder.Property(c => c.BrandsEnabled).IsRequired().HasDefaultValue(true);
         builder.Property(c => c.ItemTypesEnabled).IsRequired().HasDefaultValue(true);
+        builder.Property(c => c.SellingPricesEnabled).IsRequired().HasDefaultValue(true);
+        builder.Property(c => c.SerialNumbersEnabled).IsRequired().HasDefaultValue(true);
+        builder.Property(c => c.BatchListsEnabled).IsRequired().HasDefaultValue(true);
+        builder.Property(c => c.WarrantyPeriodsEnabled).IsRequired().HasDefaultValue(true);
 
         // PostgreSQL xmin system column as the optimistic concurrency token (ETag).
         builder.Property(c => c.RowVersion).IsRowVersion();

Backend/ERPCore/Infra/Persistence/Configurations/SubNavItemConfiguration.cs

@@ -33,6 +33,7 @@ public sealed class SubNavItemConfiguration : IEntityTypeConfiguration<SubNavIte
             new SubNavItem { SubNavItemId = 6, NavItemId = 2, Code = "products.configuration", Label = "Configuration", Href = "/dashboard/products/settings", SortOrder = 6 },
             new SubNavItem { SubNavItemId = 7, NavItemId = 9, Code = "settings.roles", Label = "Roles", Href = "/dashboard/settings/roles", SortOrder = 1 },
             new SubNavItem { SubNavItemId = 8, NavItemId = 9, Code = "settings.users", Label = "Users", Href = "/dashboard/settings/users", SortOrder = 2 },
+            new SubNavItem { SubNavItemId = 24, NavItemId = 9, Code = "settings.notification-config", Label = "Notification Config", Href = "/dashboard/settings/notification-config", SortOrder = 3 },
             new SubNavItem { SubNavItemId = 23, NavItemId = 13, Code = "sales.bundle-sales", Label = "Bundle Sales", Href = "/dashboard/sales/bundles", SortOrder = 1 },
             // Procurement (NavItemId 4) children — mirror the hub page order.
             // IDs 17-20 (not 9-12): 9-12 were already claimed by the Ledgers sub-items below;

Backend/ERPCore/Infra/Persistence/DataSeeder.cs

@@ -43,8 +43,9 @@ public static class DataSeeder
     {
         var dirty = await SeedReasonCodesAsync(db, ct);
         dirty |= await SeedItemTypesAsync(db, ct);
-       // dirty |= await SeedCompanyProfileAsync(db, ct);
+        // dirty |= await SeedCompanyProfileAsync(db, ct);
         dirty |= await SeedProductConfigAsync(db, ct);
+        dirty |= await SeedNotificationConfigAsync(db, ct);
         dirty |= await SeedSalesMastersAsync(db, ct);
         dirty |= await SeedSalesStockAsync(db, ct);
         dirty |= await SeedSalesAsync(db, ct);
@@ -100,7 +101,22 @@ public static class DataSeeder
             ConfigId = ProductConfig.SingletonId,
             SubcategoriesEnabled = true,
             BrandsEnabled = true,
-            ItemTypesEnabled = true
+            ItemTypesEnabled = true,
+            SellingPricesEnabled = true,
+            SerialNumbersEnabled = true,
+            BatchListsEnabled = true,
+            WarrantyPeriodsEnabled = true
+        });
+        return true;
+    }
+
+    private static async Task<bool> SeedNotificationConfigAsync(ErpDbContext db, CancellationToken ct)
+    {
+        if (await db.NotificationConfig.AnyAsync(c => c.NotificationConfigId == NotificationConfig.SingletonId, ct)) return false;
+
+        db.NotificationConfig.Add(new NotificationConfig
+        {
+            NotificationConfigId = NotificationConfig.SingletonId
         });
         return true;
     }

Backend/ERPCore/Infra/Persistence/ErpDbContext.cs

@@ -38,6 +38,9 @@ public class ErpDbContext : DbContext
     
     /// <summary>Singleton row (FR-MD-11).</summary>
     public DbSet<ProductConfig> ProductConfig => Set<ProductConfig>();
+    /// <summary>Singleton row for notification delivery preferences.</summary>
+    public DbSet<NotificationConfig> NotificationConfig => Set<NotificationConfig>();
+    public DbSet<NotificationConfigModule> NotificationConfigModules => Set<NotificationConfigModule>();
 
     // --- Cross-cutting (docs/10 Part C.7) ---
     public DbSet<User> Users => Set<User>();

Backend/ERPCore/Migrations/20260820100345_AddNotificationConfigModulePreferences.cs

@@ -0,0 +1,103 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+#nullable disable
+
+namespace ERPCore.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddNotificationConfigModulePreferences : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "notification_config",
+                columns: table => new
+                {
+                    NotificationConfigId = table.Column<int>(type: "integer", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "timestamp with time zone", nullable: true),
+                    UpdatedBy = table.Column<int>(type: "integer", nullable: true),
+                    xmin = table.Column<uint>(type: "xid", rowVersion: true, nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_notification_config", x => x.NotificationConfigId);
+                    table.CheckConstraint("ck_notification_config_singleton", "\"NotificationConfigId\" = 1");
+                    table.ForeignKey(
+                        name: "FK_notification_config_users_UpdatedBy",
+                        column: x => x.UpdatedBy,
+                        principalTable: "users",
+                        principalColumn: "UserId",
+                        onDelete: ReferentialAction.Restrict);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "notification_config_modules",
+                columns: table => new
+                {
+                    NotificationConfigModuleId = table.Column<int>(type: "integer", nullable: false)
+                        .Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn),
+                    NotificationConfigId = table.Column<int>(type: "integer", nullable: false),
+                    ModuleKey = table.Column<string>(type: "character varying(100)", maxLength: 100, nullable: false),
+                    EmailEnabled = table.Column<bool>(type: "boolean", nullable: false, defaultValue: false),
+                    SmsEnabled = table.Column<bool>(type: "boolean", nullable: false, defaultValue: false),
+                    InAppEnabled = table.Column<bool>(type: "boolean", nullable: false, defaultValue: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_notification_config_modules", x => x.NotificationConfigModuleId);
+                    table.ForeignKey(
+                        name: "FK_notification_config_modules_notification_config_Notificatio~",
+                        column: x => x.NotificationConfigId,
+                        principalTable: "notification_config",
+                        principalColumn: "NotificationConfigId",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.Sql("""
+                INSERT INTO sub_nav_items ("SubNavItemId", "NavItemId", "Code", "Href", "Icon", "Label", "SortOrder")
+                VALUES (24, 9, 'settings.notification-config', '/dashboard/settings/notification-config', NULL, 'Notification Config', 3)
+                ON CONFLICT ("SubNavItemId") DO UPDATE
+                SET "NavItemId" = EXCLUDED."NavItemId",
+                    "Code" = EXCLUDED."Code",
+                    "Href" = EXCLUDED."Href",
+                    "Icon" = EXCLUDED."Icon",
+                    "Label" = EXCLUDED."Label",
+                    "SortOrder" = EXCLUDED."SortOrder";
+                """);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_notification_config_UpdatedBy",
+                table: "notification_config",
+                column: "UpdatedBy");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_notification_config_modules_ModuleKey",
+                table: "notification_config_modules",
+                column: "ModuleKey",
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_notification_config_modules_NotificationConfigId",
+                table: "notification_config_modules",
+                column: "NotificationConfigId");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "notification_config_modules");
+
+            migrationBuilder.DropTable(
+                name: "notification_config");
+
+            migrationBuilder.DeleteData(
+                table: "sub_nav_items",
+                keyColumn: "SubNavItemId",
+                keyValue: 24);
+        }
+    }
+}

Backend/ERPCore/Migrations/20260820125724_AddProductConfigFeatureFlags.cs

@@ -0,0 +1,62 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ERPCore.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddProductConfigFeatureFlags : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<bool>(
+                name: "BatchListsEnabled",
+                table: "product_config",
+                type: "boolean",
+                nullable: false,
+                defaultValue: true);
+
+            migrationBuilder.AddColumn<bool>(
+                name: "SellingPricesEnabled",
+                table: "product_config",
+                type: "boolean",
+                nullable: false,
+                defaultValue: true);
+
+            migrationBuilder.AddColumn<bool>(
+                name: "SerialNumbersEnabled",
+                table: "product_config",
+                type: "boolean",
+                nullable: false,
+                defaultValue: true);
+
+            migrationBuilder.AddColumn<bool>(
+                name: "WarrantyPeriodsEnabled",
+                table: "product_config",
+                type: "boolean",
+                nullable: false,
+                defaultValue: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "BatchListsEnabled",
+                table: "product_config");
+
+            migrationBuilder.DropColumn(
+                name: "SellingPricesEnabled",
+                table: "product_config");
+
+            migrationBuilder.DropColumn(
+                name: "SerialNumbersEnabled",
+                table: "product_config");
+
+            migrationBuilder.DropColumn(
+                name: "WarrantyPeriodsEnabled",
+                table: "product_config");
+        }
+    }
+}

Backend/ERPCore/Migrations/ErpDbContextModelSnapshot.cs

@@ -2354,6 +2354,74 @@ namespace ERPCore.Migrations
                         });
                 });
 
+            modelBuilder.Entity("ERPCore.Domain.Entities.NotificationConfig", b =>
+                {
+                    b.Property<int>("NotificationConfigId")
+                        .HasColumnType("integer");
+
+                    b.Property<uint>("RowVersion")
+                        .IsConcurrencyToken()
+                        .ValueGeneratedOnAddOrUpdate()
+                        .HasColumnType("xid")
+                        .HasColumnName("xmin");
+
+                    b.Property<DateTime?>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int?>("UpdatedBy")
+                        .HasColumnType("integer");
+
+                    b.HasKey("NotificationConfigId");
+
+                    b.HasIndex("UpdatedBy");
+
+                    b.ToTable("notification_config", null, t =>
+                        {
+                            t.HasCheckConstraint("ck_notification_config_singleton", "\"NotificationConfigId\" = 1");
+                        });
+                });
+
+            modelBuilder.Entity("ERPCore.Domain.Entities.NotificationConfigModule", b =>
+                {
+                    b.Property<int>("NotificationConfigModuleId")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("NotificationConfigModuleId"));
+
+                    b.Property<bool>("EmailEnabled")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("boolean")
+                        .HasDefaultValue(false);
+
+                    b.Property<bool>("InAppEnabled")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("boolean")
+                        .HasDefaultValue(false);
+
+                    b.Property<string>("ModuleKey")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<int>("NotificationConfigId")
+                        .HasColumnType("integer");
+
+                    b.Property<bool>("SmsEnabled")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("boolean")
+                        .HasDefaultValue(false);
+
+                    b.HasKey("NotificationConfigModuleId");
+
+                    b.HasIndex("ModuleKey")
+                        .IsUnique();
+
+                    b.HasIndex("NotificationConfigId");
+
+                    b.ToTable("notification_config_modules", (string)null);
+                });
+
             modelBuilder.Entity("ERPCore.Domain.Entities.NumberSequence", b =>
                 {
                     b.Property<int>("SequenceId")
@@ -2973,6 +3041,11 @@ namespace ERPCore.Migrations
                     b.Property<int>("ConfigId")
                         .HasColumnType("integer");
 
+                    b.Property<bool>("BatchListsEnabled")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("boolean")
+                        .HasDefaultValue(true);
+
                     b.Property<bool>("BrandsEnabled")
                         .ValueGeneratedOnAdd()
                         .HasColumnType("boolean")
@@ -2989,6 +3062,16 @@ namespace ERPCore.Migrations
                         .HasColumnType("xid")
                         .HasColumnName("xmin");
 
+                    b.Property<bool>("SellingPricesEnabled")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("boolean")
+                        .HasDefaultValue(true);
+
+                    b.Property<bool>("SerialNumbersEnabled")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("boolean")
+                        .HasDefaultValue(true);
+
                     b.Property<bool>("SubcategoriesEnabled")
                         .ValueGeneratedOnAdd()
                         .HasColumnType("boolean")
@@ -3000,6 +3083,11 @@ namespace ERPCore.Migrations
                     b.Property<int?>("UpdatedBy")
                         .HasColumnType("integer");
 
+                    b.Property<bool>("WarrantyPeriodsEnabled")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("boolean")
+                        .HasDefaultValue(true);
+
                     b.HasKey("ConfigId");
 
                     b.HasIndex("UpdatedBy");
@@ -5189,6 +5277,16 @@ namespace ERPCore.Migrations
                             Status = "Active"
                         },
                         new
+                        {
+                            SubNavItemId = 24,
+                            Code = "settings.notification-config",
+                            Href = "/dashboard/settings/notification-config",
+                            Label = "Notification Config",
+                            NavItemId = 9,
+                            SortOrder = 3,
+                            Status = "Active"
+                        },
+                        new
                         {
                             SubNavItemId = 23,
                             Code = "sales.bundle-sales",
@@ -6284,6 +6382,27 @@ namespace ERPCore.Migrations
                     b.Navigation("PayrollRun");
                 });
 
+            modelBuilder.Entity("ERPCore.Domain.Entities.NotificationConfig", b =>
+                {
+                    b.HasOne("ERPCore.Domain.Entities.User", "UpdatedByUser")
+                        .WithMany()
+                        .HasForeignKey("UpdatedBy")
+                        .OnDelete(DeleteBehavior.Restrict);
+
+                    b.Navigation("UpdatedByUser");
+                });
+
+            modelBuilder.Entity("ERPCore.Domain.Entities.NotificationConfigModule", b =>
+                {
+                    b.HasOne("ERPCore.Domain.Entities.NotificationConfig", "NotificationConfig")
+                        .WithMany("Modules")
+                        .HasForeignKey("NotificationConfigId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("NotificationConfig");
+                });
+
             modelBuilder.Entity("ERPCore.Domain.Entities.PayrollLine", b =>
                 {
                     b.HasOne("ERPCore.Domain.Entities.Employee", "Employee")
@@ -7416,6 +7535,11 @@ namespace ERPCore.Migrations
                     b.Navigation("Children");
                 });
 
+            modelBuilder.Entity("ERPCore.Domain.Entities.NotificationConfig", b =>
+                {
+                    b.Navigation("Modules");
+                });
+
             modelBuilder.Entity("ERPCore.Domain.Entities.PayrollLine", b =>
                 {
                     b.Navigation("Components");

Backend/ERPCore/Program.cs

@@ -85,6 +85,8 @@ builder.Services.AddScoped<IBrandService, BrandService>();
 builder.Services.AddScoped<IItemTypeService, ItemTypeService>();
 //builder.Services.AddScoped<ICompanyProfileService, CompanyProfileService>();
 builder.Services.AddScoped<IProductConfigService, ProductConfigService>();
+builder.Services.AddSingleton<INotificationModuleCatalog, NotificationModuleCatalog>();
+builder.Services.AddScoped<INotificationConfigService, NotificationConfigService>();
 builder.Services.AddScoped<IVendorService, VendorService>();
 builder.Services.AddScoped<IWarehouseService, WarehouseService>();
 

Backend/ERPCore/Services/Interfaces/INotificationConfigService.cs

@@ -0,0 +1,12 @@
+using ERPCore.Common.Http;
+using ERPCore.Domain.Notifications;
+using ERPCore.Dtos.Notifications;
+
+namespace ERPCore.Services.Interfaces;
+
+public interface INotificationConfigService
+{
+    Task<ETagged<NotificationConfigDto>> GetAsync(CancellationToken ct = default);
+    Task<ETagged<NotificationConfigDto>> UpdateAsync(UpdateNotificationConfigRequest request, uint expectedRowVersion, CancellationToken ct = default);
+    Task<IReadOnlyList<NotificationChannel>> ResolveEnabledChannelsAsync(string moduleKey, CancellationToken ct = default);
+}

Backend/ERPCore/Services/Interfaces/INotificationModuleCatalog.cs

@@ -0,0 +1,9 @@
+using ERPCore.Domain.Notifications;
+
+namespace ERPCore.Services.Interfaces;
+
+public interface INotificationModuleCatalog
+{
+    IReadOnlyList<NotificationModuleDefinition> GetAll();
+    NotificationModuleDefinition? Find(string moduleKey);
+}

Backend/ERPCore/Services/ItemService.cs

@@ -1,6 +1,7 @@
 using ERPCore.Common.Http;
 using ERPCore.Domain.Entities;
 using ERPCore.Domain.Enums;
+using ERPCore.Dtos.Config;
 using ERPCore.Dtos.Common;
 using ERPCore.Dtos.Items;
 using ERPCore.Infra.UoW;
@@ -108,9 +109,11 @@ public sealed class ItemService : IItemService
         if (await _items.Query().AnyAsync(i => i.Sku == request.Sku, ct))
             throw new DomainException(ErrorCodes.SkuDuplicate, $"An item with SKU '{request.Sku}' already exists.", 400);
 
+        var config = (await _config.GetAsync(ct)).Value;
         await ValidateReferencesAsync(
             request.CategoryId, request.SubCategoryId, request.BrandId,
-            request.BaseUomId, request.DefaultVendorId, ct);
+            request.BaseUomId, request.DefaultVendorId, config, ct);
+        ValidateFeatureConfiguration(request, config);
 
         ItemContent.ValidatePair(request.ContentQty, request.ContentUnit);
         var (contentBaseQty, contentBaseUnit) = ItemContent.Normalize(request.ContentQty, request.ContentUnit);
@@ -163,9 +166,11 @@ public sealed class ItemService : IItemService
             && await _items.Query().AnyAsync(i => i.Sku == request.Sku && i.ItemId != itemId, ct))
             throw new DomainException(ErrorCodes.SkuDuplicate, $"An item with SKU '{request.Sku}' already exists.", 400);
 
+        var config = (await _config.GetAsync(ct)).Value;
         await ValidateReferencesAsync(
             request.CategoryId, request.SubCategoryId, request.BrandId,
-            request.BaseUomId, request.DefaultVendorId, ct);
+            request.BaseUomId, request.DefaultVendorId, config, ct);
+        ValidateFeatureConfiguration(request, config);
 
         // The base UOM is the sole meaning of every quantity recorded against this item —
         // stock layers, ledger rows and document lines are all plain counts of it. Once any
@@ -280,10 +285,9 @@ public sealed class ItemService : IItemService
     /// it is advisory and honoured by the frontend only (docs/11 §2.8).
     /// </summary>
     private async Task ValidateReferencesAsync(
-        int categoryId, int? subCategoryId, int? brandId, int baseUomId, int? defaultVendorId, CancellationToken ct)
+        int categoryId, int? subCategoryId, int? brandId, int baseUomId, int? defaultVendorId,
+        ProductConfigDto config, CancellationToken ct)
     {
-        var config = (await _config.GetAsync(ct)).Value;
-
         if (!await _categories.Query().AnyAsync(c => c.CategoryId == categoryId, ct))
             throw new DomainException(ErrorCodes.Validation, $"Category {categoryId} does not exist.", 422);
 
@@ -337,6 +341,46 @@ public sealed class ItemService : IItemService
         }
     }
 
+    private static void ValidateFeatureConfiguration(CreateItemRequest request, ProductConfigDto config)
+        => ValidateFeatureConfiguration(
+            request.SellingMinPrice, request.SellingMaxPrice, request.SellingFlatPrice,
+            request.TrackingMode, request.Warranty, config);
+
+    private static void ValidateFeatureConfiguration(UpdateItemRequest request, ProductConfigDto config)
+        => ValidateFeatureConfiguration(
+            request.SellingMinPrice, request.SellingMaxPrice, request.SellingFlatPrice,
+            request.TrackingMode, request.Warranty, config);
+
+    private static void ValidateFeatureConfiguration(
+        decimal? sellingMinPrice, decimal? sellingMaxPrice, decimal? sellingFlatPrice,
+        TrackingMode trackingMode, Warranty warranty, ProductConfigDto config)
+    {
+        if (!config.SellingPricesEnabled &&
+            (sellingMinPrice is not null || sellingMaxPrice is not null || sellingFlatPrice is not null))
+            throw new DomainException(
+                ErrorCodes.ConfigDisabled,
+                "Selling prices are disabled in the product configuration; sellingMinPrice, sellingMaxPrice and sellingFlatPrice must be null.",
+                422);
+
+        if (!config.SerialNumbersEnabled && trackingMode == TrackingMode.Serial)
+            throw new DomainException(
+                ErrorCodes.ConfigDisabled,
+                "Serial numbers are disabled in the product configuration; trackingMode cannot be Serial.",
+                422);
+
+        if (!config.BatchListsEnabled && trackingMode == TrackingMode.Batch)
+            throw new DomainException(
+                ErrorCodes.ConfigDisabled,
+                "Batch lists are disabled in the product configuration; trackingMode cannot be Batch.",
+                422);
+
+        if (!config.WarrantyPeriodsEnabled && warranty == Warranty.Warranty)
+            throw new DomainException(
+                ErrorCodes.ConfigDisabled,
+                "Warranty periods are disabled in the product configuration; warranty cannot be Warranty.",
+                422);
+    }
+
     /// <summary>
     /// A warranty-tracked item must declare a coverage period (one of
     /// <see cref="WarrantyPeriods.AllowedMonths"/>); a non-warranty item carries none —

Backend/ERPCore/Services/NotificationConfigService.cs

@@ -0,0 +1,143 @@
+using ERPCore.Common.Http;
+using ERPCore.Domain.Entities;
+using ERPCore.Domain.Notifications;
+using ERPCore.Dtos.Notifications;
+using ERPCore.Infra.Auth;
+using ERPCore.Infra.UoW;
+using ERPCore.Repositories.Interfaces;
+using ERPCore.Services.Interfaces;
+using ERPCore.System.Errors;
+using Microsoft.EntityFrameworkCore;
+
+namespace ERPCore.Services;
+
+public sealed class NotificationConfigService : INotificationConfigService
+{
+    private readonly IRepository<NotificationConfig> _config;
+    private readonly IRepository<NotificationConfigModule> _modules;
+    private readonly INotificationModuleCatalog _catalog;
+    private readonly ICurrentUser _currentUser;
+    private readonly IUnitOfWork _uow;
+
+    public NotificationConfigService(
+        IRepository<NotificationConfig> config,
+        IRepository<NotificationConfigModule> modules,
+        INotificationModuleCatalog catalog,
+        ICurrentUser currentUser,
+        IUnitOfWork uow)
+    {
+        _config = config;
+        _modules = modules;
+        _catalog = catalog;
+        _currentUser = currentUser;
+        _uow = uow;
+    }
+
+    public async Task<ETagged<NotificationConfigDto>> GetAsync(CancellationToken ct = default)
+    {
+        var config = await _config.Query().AsNoTracking()
+            .Include(c => c.Modules)
+            .FirstOrDefaultAsync(c => c.NotificationConfigId == NotificationConfig.SingletonId, ct)
+            ?? throw new NotFoundException("Notification configuration has not been seeded.");
+
+        return new ETagged<NotificationConfigDto>(Map(config), config.RowVersion);
+    }
+
+    public async Task<ETagged<NotificationConfigDto>> UpdateAsync(UpdateNotificationConfigRequest request, uint expectedRowVersion, CancellationToken ct = default)
+    {
+        var config = await _config.Query()
+            .Include(c => c.Modules)
+            .FirstOrDefaultAsync(c => c.NotificationConfigId == NotificationConfig.SingletonId, ct)
+            ?? throw new NotFoundException("Notification configuration has not been seeded.");
+
+        if (config.RowVersion != expectedRowVersion)
+            throw new DomainException(ErrorCodes.ConcurrencyConflict, "The notification configuration was modified by another request.", 412);
+
+        var catalog = _catalog.GetAll();
+        var inputs = request.Modules ?? new List<UpdateNotificationModuleRequest>();
+        if (inputs.Any(x => string.IsNullOrWhiteSpace(x.ModuleKey)))
+            throw new DomainException(ErrorCodes.Validation, "Notification module keys cannot be empty.", 400);
+        if (inputs.Select(x => x.ModuleKey.Trim()).Distinct(StringComparer.OrdinalIgnoreCase).Count() != inputs.Count)
+            throw new DomainException(ErrorCodes.Validation, "Duplicate notification module keys are not allowed.", 400);
+
+        var byKey = inputs.ToDictionary(x => x.ModuleKey.Trim(), StringComparer.OrdinalIgnoreCase);
+        var unknown = byKey.Keys.Where(k => catalog.All(m => !string.Equals(m.Key, k, StringComparison.OrdinalIgnoreCase))).ToList();
+        if (unknown.Count > 0)
+            throw new DomainException(ErrorCodes.Validation, $"Unknown notification module key(s): {string.Join(", ", unknown)}.", 422);
+
+        var missing = catalog.Where(m => !byKey.ContainsKey(m.Key)).Select(m => m.Key).ToList();
+        if (missing.Count > 0)
+            throw new DomainException(ErrorCodes.Validation, $"Missing notification module settings for: {string.Join(", ", missing)}.", 422);
+
+        config.Modules.Clear();
+        foreach (var module in catalog)
+        {
+            var input = byKey[module.Key];
+            config.Modules.Add(new NotificationConfigModule
+            {
+                NotificationConfigId = config.NotificationConfigId,
+                ModuleKey = module.Key,
+                EmailEnabled = input.EmailEnabled!.Value,
+                SmsEnabled = input.SmsEnabled!.Value,
+                InAppEnabled = input.InAppEnabled!.Value
+            });
+        }
+
+        config.UpdatedAt = DateTime.UtcNow;
+        config.UpdatedBy = _currentUser.AuditUserId;
+
+        await SaveGuardingConcurrencyAsync(ct);
+        return new ETagged<NotificationConfigDto>(Map(config), config.RowVersion);
+    }
+
+    public async Task<IReadOnlyList<NotificationChannel>> ResolveEnabledChannelsAsync(string moduleKey, CancellationToken ct = default)
+    {
+        var key = moduleKey?.Trim();
+        if (string.IsNullOrWhiteSpace(key)) return Array.Empty<NotificationChannel>();
+
+        var row = await _modules.Query().AsNoTracking()
+            .FirstOrDefaultAsync(m => m.ModuleKey == key, ct);
+
+        if (row is null) return Array.Empty<NotificationChannel>();
+
+        var channels = new List<NotificationChannel>(3);
+        if (row.EmailEnabled) channels.Add(NotificationChannel.Email);
+        if (row.SmsEnabled) channels.Add(NotificationChannel.Sms);
+        if (row.InAppEnabled) channels.Add(NotificationChannel.InApp);
+        return channels;
+    }
+
+    private async Task SaveGuardingConcurrencyAsync(CancellationToken ct)
+    {
+        try
+        {
+            await _uow.SaveChangesAsync(ct);
+        }
+        catch (DbUpdateConcurrencyException)
+        {
+            throw new DomainException(ErrorCodes.ConcurrencyConflict, "The notification configuration was modified by another request.", 412);
+        }
+    }
+
+    private NotificationConfigDto Map(NotificationConfig config)
+    {
+        var rows = config.Modules
+            .ToDictionary(m => m.ModuleKey, m => m, StringComparer.OrdinalIgnoreCase);
+
+        var modules = _catalog.GetAll()
+            .Select(m =>
+            {
+                rows.TryGetValue(m.Key, out var row);
+                return new NotificationModuleConfigDto(
+                    m.Key,
+                    m.Label,
+                    m.Description,
+                    row?.EmailEnabled ?? false,
+                    row?.SmsEnabled ?? false,
+                    row?.InAppEnabled ?? false);
+            })
+            .ToList();
+
+        return new NotificationConfigDto(modules, config.UpdatedAt, config.UpdatedBy);
+    }
+}

Backend/ERPCore/Services/NotificationModuleCatalog.cs

@@ -0,0 +1,35 @@
+using System.Reflection;
+using ERPCore.Domain.Notifications;
+using ERPCore.Domain.Notifications.Modules;
+using ERPCore.Services.Interfaces;
+
+namespace ERPCore.Services;
+
+public sealed class NotificationModuleCatalog : INotificationModuleCatalog
+{
+    private readonly IReadOnlyList<NotificationModuleDefinition> _modules;
+
+    public NotificationModuleCatalog()
+    {
+        var moduleType = typeof(SaleCreateNotificationModule).Assembly;
+        _modules = moduleType.GetTypes()
+            .Select(t => new { Type = t, Attr = t.GetCustomAttribute<NotificationModuleAttribute>() })
+            .Where(x => x.Attr is not null)
+            .Select(x => new NotificationModuleDefinition(x.Attr!.Key, x.Attr.Label, x.Attr.Description, x.Attr.SortOrder))
+            .OrderBy(x => x.SortOrder)
+            .ThenBy(x => x.Key, StringComparer.Ordinal)
+            .ToList();
+
+        var duplicates = _modules.GroupBy(m => m.Key, StringComparer.OrdinalIgnoreCase)
+            .Where(g => g.Count() > 1)
+            .Select(g => g.Key)
+            .ToList();
+        if (duplicates.Count > 0)
+            throw new InvalidOperationException($"Duplicate notification module key(s) found: {string.Join(", ", duplicates)}.");
+    }
+
+    public IReadOnlyList<NotificationModuleDefinition> GetAll() => _modules;
+
+    public NotificationModuleDefinition? Find(string moduleKey)
+        => _modules.FirstOrDefault(m => string.Equals(m.Key, moduleKey, StringComparison.OrdinalIgnoreCase));
+}

Backend/ERPCore/Services/ProductConfigService.cs

@@ -12,7 +12,7 @@ namespace ERPCore.Services;
 
 /// <summary>
 /// Product configuration service (FR-MD-11) over the singleton row seeded by DataSeeder.
-/// Reads are never gated — only writes consult the flags — so switching a feature off
+/// Reads are never gated - only writes consult the flags - so switching a feature off
 /// leaves existing data readable (docs/11-BACKEND-PHASE1.md §2.8).
 /// </summary>
 public sealed class ProductConfigService : IProductConfigService
@@ -46,11 +46,15 @@ public sealed class ProductConfigService : IProductConfigService
         if (config.RowVersion != expectedRowVersion)
             throw new DomainException(ErrorCodes.ConcurrencyConflict, "The configuration was modified by another request.", 412);
 
-        // Non-null by [Required] on the nullable bools — an omitted flag is a 400, so the
+        // Non-null by [Required] on the nullable bools - an omitted flag is a 400, so the
         // model binder has already rejected anything that would reach here with a null.
         config.SubcategoriesEnabled = request.SubcategoriesEnabled!.Value;
         config.BrandsEnabled = request.BrandsEnabled!.Value;
         config.ItemTypesEnabled = request.ItemTypesEnabled!.Value;
+        config.SellingPricesEnabled = request.SellingPricesEnabled!.Value;
+        config.SerialNumbersEnabled = request.SerialNumbersEnabled!.Value;
+        config.BatchListsEnabled = request.BatchListsEnabled!.Value;
+        config.WarrantyPeriodsEnabled = request.WarrantyPeriodsEnabled!.Value;
         config.UpdatedAt = DateTime.UtcNow;
         config.UpdatedBy = _currentUser.AuditUserId;
 
@@ -67,5 +71,7 @@ public sealed class ProductConfigService : IProductConfigService
     }
 
     private static ProductConfigDto Map(ProductConfig c) => new(
-        c.SubcategoriesEnabled, c.BrandsEnabled, c.ItemTypesEnabled, c.UpdatedAt, c.UpdatedBy);
+        c.SubcategoriesEnabled, c.BrandsEnabled, c.ItemTypesEnabled,
+        c.SellingPricesEnabled, c.SerialNumbersEnabled, c.BatchListsEnabled, c.WarrantyPeriodsEnabled,
+        c.UpdatedAt, c.UpdatedBy);
 }

Frontend/erp-system/app/dashboard/products/new/page.tsx

@@ -105,6 +105,7 @@ export default function NewItemPage() {
   const [contentQty, setContentQty] = useState("")
   const [contentUnit, setContentUnit] = useState<MeasureUnit | null>(null)
   const [stockNature, setStockNature] = useState<StockNature>("Stocked")
+  const [trackingMode, setTrackingMode] = useState<"None" | "Batch" | "Serial">("None")
   const [loadError, setLoadError] = useState<string | null>(null)
 
   const [productName, setProductName] = useState("")
@@ -129,15 +130,12 @@ export default function NewItemPage() {
   const [removedVariantKeys, setRemovedVariantKeys] = useState<Set<string>>(new Set())
 
   // Sales pricing (FR-MD-01). "stock" ⇒ sellingFlatPrice sent as null (sell at FIFO value);
-  // "fixed" ⇒ every variant must carry a price. `fixValue` is the shared default that
-  // pre-fills rows; a per-key entry in `pricesByKey` overrides it for that one row only.
+  // "fixed" ⇒ every variant must carry a price. `defaultFlatPrice` is a bulk-fill helper;
+  // each row keeps its own flat price in `pricesByKey`.
   const [priceMode, setPriceMode] = useState<"stock" | "fixed">("stock")
-  const [fixValue, setFixValue] = useState<string>("")
+  const [defaultFlatPrice, setDefaultFlatPrice] = useState<string>("")
   const [pricesByKey, setPricesByKey] = useState<Record<string, string>>({})
   const [priceErrors, setPriceErrors] = useState<Record<string, string>>({})
-  const [sellingMinPrice, setSellingMinPrice] = useState("")
-  const [sellingMaxPrice, setSellingMaxPrice] = useState("")
-  const [sellingFlatPrice, setSellingFlatPrice] = useState("")
 
   // Warranty (FR-MD-01). Applies to every generated variant — there is no per-variant override.
   const [warranty, setWarranty] = useState<Warranty>("NonWarranty")
@@ -147,8 +145,9 @@ export default function NewItemPage() {
   const [submitError, setSubmitError] = useState<string | null>(null)
   const [submitting, setSubmitting] = useState(false)
 
-  // A row shows its own override if set, otherwise it follows the shared fix value.
-  const priceFor = (key: string) => pricesByKey[key] ?? fixValue
+  // Each row owns its own flat price. The default field is only a bulk-fill helper.
+  const priceFor = (key: string) => pricesByKey[key] ?? ""
+  const variantPriceFor = (variantKey: string, kind: "min" | "max" | "flat") => pricesByKey[`${variantKey}::${kind}`] ?? ""
 
   useEffect(() => {
     Promise.all([
@@ -184,6 +183,35 @@ export default function NewItemPage() {
       .catch(() => setSubCategories([]))
   }, [categoryId, config?.subcategoriesEnabled])
 
+  useEffect(() => {
+    if (!config) return
+
+    if (!config.serialNumbersEnabled && trackingMode === "Serial") {
+      setTrackingMode("None")
+    }
+    if (!config.batchListsEnabled && trackingMode === "Batch") {
+      setTrackingMode("None")
+    }
+    if (!config.warrantyPeriodsEnabled && warranty === "Warranty") {
+      setWarranty("NonWarranty")
+      setWarrantyPeriodMonths(null)
+    }
+    if (!config.sellingPricesEnabled) {
+      setPriceMode("stock")
+      setDefaultFlatPrice("")
+      setPricesByKey({})
+      setPriceErrors({})
+    }
+  }, [
+    config,
+    trackingMode,
+    warranty,
+    config?.serialNumbersEnabled,
+    config?.batchListsEnabled,
+    config?.warrantyPeriodsEnabled,
+    config?.sellingPricesEnabled,
+  ])
+
   const brandLabel = (brands ?? []).find((b) => b.brandId === brandId)?.name ?? ""
   /**
    * The product being built ("Coca Cola"), typed rather than derived. It names every generated
@@ -358,7 +386,7 @@ export default function NewItemPage() {
     if (measurableCheckedCount > 1) {
       nextErrors.measurable = "Only one measurement dimension can be used at a time."
     }
-    if (warranty === "Warranty" && warrantyPeriodMonths === null) {
+    if (config?.warrantyPeriodsEnabled && warranty === "Warranty" && warrantyPeriodMonths === null) {
       nextErrors.warrantyPeriodMonths = "Select a warranty period"
     }
     // Should never fire — addValue is the real gate — so it catches stale state only.
@@ -377,7 +405,7 @@ export default function NewItemPage() {
     setErrors(nextErrors)
     // In fixed mode, block the whole submit until every variant has a price > 0.
     const nextPriceErrors =
-      priceMode === "fixed" ? validateVariantPrices(variants.map((v) => v.key), priceFor) : {}
+      config?.sellingPricesEnabled && priceMode === "fixed" ? validateVariantPrices(variants.map((v) => v.key), priceFor) : {}
     setPriceErrors(nextPriceErrors)
     if (Object.keys(nextErrors).length > 0 || Object.keys(nextPriceErrors).length > 0) return
     if (baseUomId === null) {
@@ -388,6 +416,17 @@ export default function NewItemPage() {
     setSubmitting(true)
     let created = 0
     try {
+      const effectiveTrackingMode =
+        !config?.serialNumbersEnabled && trackingMode === "Serial"
+          ? "None"
+          : !config?.batchListsEnabled && trackingMode === "Batch"
+            ? "None"
+            : trackingMode
+      const effectiveWarranty = config?.warrantyPeriodsEnabled ? warranty : "NonWarranty"
+      const effectiveWarrantyPeriodMonths =
+        config?.warrantyPeriodsEnabled && effectiveWarranty === "Warranty" ? warrantyPeriodMonths : null
+      const allowSellingPrices = !!config?.sellingPricesEnabled
+      const sendFlatPrices = allowSellingPrices && priceMode === "fixed"
       for (const variant of variants) {
         const content = contentForVariant(variant)
         await itemsApi.create({
@@ -401,14 +440,21 @@ export default function NewItemPage() {
           brandId,
           baseUomId,
           stockNature,
-          trackingMode: "None",
-          warranty,
-          warrantyPeriodMonths: warranty === "Warranty" ? warrantyPeriodMonths : null,
-          sellingMinPrice: null,
-          sellingMaxPrice: null,
-          sellingMinPrice: sellingMinPrice.trim() ? Number(sellingMinPrice) : null,
-          sellingMaxPrice: sellingMaxPrice.trim() ? Number(sellingMaxPrice) : null,
-          sellingFlatPrice: priceMode === "fixed" ? Number(priceFor(variant.key)) : (sellingFlatPrice.trim() ? Number(sellingFlatPrice) : null),
+          trackingMode: effectiveTrackingMode,
+          warranty: effectiveWarranty,
+          warrantyPeriodMonths: effectiveWarrantyPeriodMonths,
+          sellingMinPrice:
+            allowSellingPrices && variantPriceFor(variant.key, "min").trim()
+              ? Number(variantPriceFor(variant.key, "min"))
+              : null,
+          sellingMaxPrice:
+            allowSellingPrices && variantPriceFor(variant.key, "max").trim()
+              ? Number(variantPriceFor(variant.key, "max"))
+              : null,
+          sellingFlatPrice:
+            allowSellingPrices && sendFlatPrices && priceFor(variant.key).trim()
+              ? Number(priceFor(variant.key))
+              : null,
           // Each variant carries its OWN size when a measurement dimension supplied one;
           // otherwise the shared form-level pair, which is correct when the varying dimension
           // isn't size (colour variants of one 500 ml bottle all hold 500 ml).
@@ -644,168 +690,170 @@ export default function NewItemPage() {
                 </SelectContent>
               </Select>
             </div>
-          </div>
-
-          <div className="flex flex-col gap-4 rounded-xl border p-5">
-            <div>
-              <h2 className="text-lg font-semibold text-foreground">Selling prices</h2>
+            <div className="flex flex-col gap-2">
+              <Label className="text-base">Tracking mode</Label>
+              <Select<"None" | "Batch" | "Serial"> value={trackingMode} onValueChange={(v) => v && setTrackingMode(v)}>
+                <SelectTrigger className="h-12! w-full text-base">
+                  <SelectValue />
+                </SelectTrigger>
+                <SelectContent>
+                  <SelectItem value="None" className="text-base">None</SelectItem>
+                  {config?.batchListsEnabled && <SelectItem value="Batch" className="text-base">Batch</SelectItem>}
+                  {config?.serialNumbersEnabled && <SelectItem value="Serial" className="text-base">Serial</SelectItem>}
+                </SelectContent>
+              </Select>
               <p className="text-sm text-muted-foreground">
-                Optional values for the item. Leave any field blank if it does not apply.
+                {config?.serialNumbersEnabled ? (
+                  <>
+                    Choose <span className="font-medium">Serial</span> if each unit needs its own serial number on receipt.
+                  </>
+                ) : config?.batchListsEnabled ? (
+                  <>
+                    Batch tracking is available; serial tracking is currently disabled in product settings.
+                  </>
+                ) : (
+                  <>
+                    Tracking is currently disabled in product settings.
+                  </>
+                )}
               </p>
             </div>
-            <div className="grid grid-cols-1 gap-4 sm:grid-cols-3">
-              <div className="flex flex-col gap-2">
-                <Label className="text-base">Selling min price</Label>
-                <Input
-                  type="number"
-                  min="0"
-                  step="0.01"
-                  inputMode="decimal"
-                  value={sellingMinPrice}
-                  onChange={(e) => setSellingMinPrice(e.target.value)}
-                  placeholder="Optional"
-                  className="h-11 text-base"
-                />
-              </div>
-              <div className="flex flex-col gap-2">
-                <Label className="text-base">Selling max price</Label>
-                <Input
-                  type="number"
-                  min="0"
-                  step="0.01"
-                  inputMode="decimal"
-                  value={sellingMaxPrice}
-                  onChange={(e) => setSellingMaxPrice(e.target.value)}
-                  placeholder="Optional"
-                  className="h-11 text-base"
-                />
-              </div>
-              <div className="flex flex-col gap-2">
-                <Label className="text-base">Selling flat price</Label>
-                <Input
-                  type="number"
-                  min="0"
-                  step="0.01"
-                  inputMode="decimal"
-                  value={sellingFlatPrice}
-                  onChange={(e) => setSellingFlatPrice(e.target.value)}
-                  placeholder="Optional"
-                  className="h-11 text-base"
-                />
-              </div>
-            </div>
           </div>
 
-          {/* Sales pricing (FR-MD-01). The toggle is frontend-only: "stock" sends
-              sellingFlatPrice=null (sold at FIFO value); "fixed" requires a price per variant. */}
-          <div className="flex flex-col gap-4 rounded-xl border p-5">
-            <div>
-              <h2 className="text-lg font-semibold text-foreground">Sale price</h2>
-              <p className="text-sm text-muted-foreground">
-                Choose a fixed selling price, or leave it to the item&apos;s stock value.
-              </p>
-            </div>
+          {config?.sellingPricesEnabled && (
+            <div className="flex flex-col gap-4 rounded-xl border p-5">
+              <div className="flex flex-col gap-2 lg:flex-row lg:items-end lg:justify-between">
+                <div>
+                  <h2 className="text-lg font-semibold text-foreground">Variant selling prices</h2>
+                  <p className="text-sm text-muted-foreground">
+                    Edit the min, max, and flat price per generated variant. The bulk default only fills the flat column.
+                  </p>
+                </div>
 
-            <div className="inline-flex w-fit rounded-lg border p-1">
-              <button
-                type="button"
-                onClick={() => setPriceMode("stock")}
-                className={cn(
-                  "rounded-md px-4 py-2 text-base font-medium transition-colors",
-                  priceMode === "stock" ? "bg-primary text-primary-foreground" : "text-muted-foreground hover:bg-muted/50",
-                )}
-              >
-                Use stock value
-              </button>
-              <button
-                type="button"
-                onClick={() => setPriceMode("fixed")}
-                className={cn(
-                  "rounded-md px-4 py-2 text-base font-medium transition-colors",
-                  priceMode === "fixed" ? "bg-primary text-primary-foreground" : "text-muted-foreground hover:bg-muted/50",
-                )}
-              >
-                Fixed price
-              </button>
-            </div>
+                <div className="inline-flex w-fit rounded-lg border p-1">
+                  <button
+                    type="button"
+                    onClick={() => setPriceMode("stock")}
+                    className={cn(
+                      "rounded-md px-4 py-2 text-base font-medium transition-colors",
+                      priceMode === "stock" ? "bg-primary text-primary-foreground" : "text-muted-foreground hover:bg-muted/50",
+                    )}
+                  >
+                    Use stock value
+                  </button>
+                  <button
+                    type="button"
+                    onClick={() => setPriceMode("fixed")}
+                    className={cn(
+                      "rounded-md px-4 py-2 text-base font-medium transition-colors",
+                      priceMode === "fixed" ? "bg-primary text-primary-foreground" : "text-muted-foreground hover:bg-muted/50",
+                    )}
+                  >
+                    Fixed price
+                  </button>
+                </div>
+              </div>
 
-            {priceMode === "fixed" && (
-              <div className="flex max-w-xs flex-col gap-2">
-                <Label className="text-base">Fix value (applies to all variants)</Label>
-                <Input
-                  type="number"
-                  min="0"
-                  step="0.01"
-                  inputMode="decimal"
-                  value={fixValue}
-                  onChange={(e) => setFixValue(e.target.value)}
-                  placeholder="0.00"
-                  className="h-11 text-base"
-                />
+              {priceMode === "fixed" && (
+                <div className="flex max-w-xl flex-wrap items-end gap-3">
+                  <div className="flex min-w-56 flex-1 flex-col gap-2">
+                    <Label className="text-base">Bulk default flat price</Label>
+                    <Input
+                      type="number"
+                      min="0"
+                      step="0.01"
+                      inputMode="decimal"
+                      value={defaultFlatPrice}
+                      onChange={(e) => setDefaultFlatPrice(e.target.value)}
+                      placeholder="0.00"
+                      className="h-11 text-base"
+                    />
+                  </div>
+                  <Button
+                    type="button"
+                    variant="outline"
+                    onClick={() => {
+                      const raw = defaultFlatPrice.trim()
+                      if (!raw) return
+                      setPricesByKey((prev) => {
+                        const next = { ...prev }
+                        for (const variant of variants) {
+                          if (next[variant.key] == null || next[variant.key].trim() === "") {
+                            next[variant.key] = raw
+                          }
+                        }
+                        return next
+                      })
+                    }}
+                  >
+                    Fill blank flat prices
+                  </Button>
+                  <p className="text-sm text-muted-foreground">
+                    This copies the same value into blank flat-price cells only.
+                  </p>
+                </div>
+              )}
+            </div>
+          )}
+
+          {config?.warrantyPeriodsEnabled && (
+            <div className="flex flex-col gap-4 rounded-xl border p-5">
+              <div>
+                <h2 className="text-lg font-semibold text-foreground">Warranty</h2>
                 <p className="text-sm text-muted-foreground">
-                  Edit any row below to give that variant a different price.
+                  Mark whether every generated variant is sold under warranty.
                 </p>
               </div>
-            )}
-          </div>
 
-          {/* Warranty (FR-MD-01). Frontend-only toggle, mirrors the Sale price bar above. */}
-          <div className="flex flex-col gap-4 rounded-xl border p-5">
-            <div>
-              <h2 className="text-lg font-semibold text-foreground">Warranty</h2>
-              <p className="text-sm text-muted-foreground">
-                Mark whether every generated variant is sold under warranty.
-              </p>
-            </div>
-
-            <div className="inline-flex w-fit rounded-lg border p-1">
-              <button
-                type="button"
-                onClick={() => {
-                  setWarranty("NonWarranty")
-                  setWarrantyPeriodMonths(null)
-                }}
-                className={cn(
-                  "rounded-md px-4 py-2 text-base font-medium transition-colors",
-                  warranty === "NonWarranty" ? "bg-primary text-primary-foreground" : "text-muted-foreground hover:bg-muted/50",
-                )}
-              >
-                Non-Warranty
-              </button>
-              <button
-                type="button"
-                onClick={() => setWarranty("Warranty")}
-                className={cn(
-                  "rounded-md px-4 py-2 text-base font-medium transition-colors",
-                  warranty === "Warranty" ? "bg-primary text-primary-foreground" : "text-muted-foreground hover:bg-muted/50",
-                )}
-              >
-                Warranty
-              </button>
-            </div>
-
-            {warranty === "Warranty" && (
-              <div className="flex flex-col gap-1.5">
-                <Label>Warranty period</Label>
-                <Select<WarrantyPeriodMonths>
-                  value={warrantyPeriodMonths}
-                  onValueChange={(v) => v && setWarrantyPeriodMonths(v)}
+              <div className="inline-flex w-fit rounded-lg border p-1">
+                <button
+                  type="button"
+                  onClick={() => {
+                    setWarranty("NonWarranty")
+                    setWarrantyPeriodMonths(null)
+                  }}
+                  className={cn(
+                    "rounded-md px-4 py-2 text-base font-medium transition-colors",
+                    warranty === "NonWarranty" ? "bg-primary text-primary-foreground" : "text-muted-foreground hover:bg-muted/50",
+                  )}
                 >
-                  <SelectTrigger className="h-11! w-48 text-base" aria-invalid={!!errors.warrantyPeriodMonths}>
-                    <SelectValue placeholder="Select period" />
-                  </SelectTrigger>
-                  <SelectContent>
-                    {WARRANTY_PERIOD_MONTHS_OPTIONS.map((months) => (
-                      <SelectItem key={months} value={months} className="text-base">
-                        {months} months
-                      </SelectItem>
-                    ))}
-                  </SelectContent>
-                </Select>
-                <FieldError errors={[errors.warrantyPeriodMonths ? { message: errors.warrantyPeriodMonths } : undefined]} />
+                  Non-Warranty
+                </button>
+                <button
+                  type="button"
+                  onClick={() => setWarranty("Warranty")}
+                  className={cn(
+                    "rounded-md px-4 py-2 text-base font-medium transition-colors",
+                    warranty === "Warranty" ? "bg-primary text-primary-foreground" : "text-muted-foreground hover:bg-muted/50",
+                  )}
+                >
+                  Warranty
+                </button>
               </div>
-            )}
-          </div>
+
+              {warranty === "Warranty" && (
+                <div className="flex flex-col gap-1.5">
+                  <Label>Warranty period</Label>
+                  <Select<WarrantyPeriodMonths>
+                    value={warrantyPeriodMonths}
+                    onValueChange={(v) => v && setWarrantyPeriodMonths(v)}
+                  >
+                    <SelectTrigger className="h-11! w-48 text-base" aria-invalid={!!errors.warrantyPeriodMonths}>
+                      <SelectValue placeholder="Select period" />
+                    </SelectTrigger>
+                    <SelectContent>
+                      {WARRANTY_PERIOD_MONTHS_OPTIONS.map((months) => (
+                        <SelectItem key={months} value={months} className="text-base">
+                          {months} months
+                        </SelectItem>
+                      ))}
+                    </SelectContent>
+                  </Select>
+                  <FieldError errors={[errors.warrantyPeriodMonths ? { message: errors.warrantyPeriodMonths } : undefined]} />
+                </div>
+              )}
+            </div>
+          )}
 
           {/* itemTypesEnabled is advisory — the server cannot enforce it (items hold no
               item-type reference), so this section IS the enforcement. */}
@@ -975,7 +1023,11 @@ export default function NewItemPage() {
                       <TableHead className="h-11 px-3 text-sm">SKU</TableHead>
                       <TableHead className="h-11 px-3 text-sm">Content</TableHead>
                       {priceMode === "fixed" && (
-                        <TableHead className="h-11 px-3 text-sm">Sale price</TableHead>
+                        <>
+                          <TableHead className="h-11 px-3 text-sm">Min price</TableHead>
+                          <TableHead className="h-11 px-3 text-sm">Max price</TableHead>
+                          <TableHead className="h-11 px-3 text-sm">Flat price</TableHead>
+                        </>
                       )}
                       {/* Quantity column removed 2026-07-17: there is no `initialQty` on the
                           Item contract and no initial-receipt flow — stock arrives via a GRN.
@@ -999,29 +1051,55 @@ export default function NewItemPage() {
                           {contentLabelFor(variant)}
                         </TableCell>
                         {priceMode === "fixed" && (
-                          <TableCell className="px-3 py-2.5">
-                            <Input
-                              type="number"
-                              min="0"
-                              step="0.01"
-                              inputMode="decimal"
-                              value={priceFor(variant.key)}
-                              onChange={(e) => {
-                                const value = e.target.value
-                                setPricesByKey((prev) => ({ ...prev, [variant.key]: value }))
-                                setPriceErrors((prev) => {
-                                  if (!prev[variant.key]) return prev
-                                  const next = { ...prev }
-                                  delete next[variant.key]
-                                  return next
-                                })
-                              }}
-                              placeholder="0.00"
-                              aria-invalid={!!priceErrors[variant.key]}
-                              className="h-10 w-28 text-base"
-                            />
-                            <FieldError errors={[priceErrors[variant.key] ? { message: priceErrors[variant.key] } : undefined]} />
-                          </TableCell>
+                          <>
+                            <TableCell className="px-3 py-2.5">
+                              <Input
+                                type="number"
+                                min="0"
+                                step="0.01"
+                                inputMode="decimal"
+                                value={pricesByKey[`${variant.key}::min`] ?? ""}
+                                onChange={(e) => setPricesByKey((prev) => ({ ...prev, [`${variant.key}::min`]: e.target.value }))}
+                                placeholder="0.00"
+                                className="h-10 w-28 text-base"
+                              />
+                            </TableCell>
+                            <TableCell className="px-3 py-2.5">
+                              <Input
+                                type="number"
+                                min="0"
+                                step="0.01"
+                                inputMode="decimal"
+                                value={pricesByKey[`${variant.key}::max`] ?? ""}
+                                onChange={(e) => setPricesByKey((prev) => ({ ...prev, [`${variant.key}::max`]: e.target.value }))}
+                                placeholder="0.00"
+                                className="h-10 w-28 text-base"
+                              />
+                            </TableCell>
+                            <TableCell className="px-3 py-2.5">
+                              <Input
+                                type="number"
+                                min="0"
+                                step="0.01"
+                                inputMode="decimal"
+                                value={priceFor(variant.key)}
+                                onChange={(e) => {
+                                  const value = e.target.value
+                                  setPricesByKey((prev) => ({ ...prev, [variant.key]: value }))
+                                  setPriceErrors((prev) => {
+                                    if (!prev[variant.key]) return prev
+                                    const next = { ...prev }
+                                    delete next[variant.key]
+                                    return next
+                                  })
+                                }}
+                                placeholder="0.00"
+                                aria-invalid={!!priceErrors[variant.key]}
+                                className="h-10 w-28 text-base"
+                              />
+                              <FieldError errors={[priceErrors[variant.key] ? { message: priceErrors[variant.key] } : undefined]} />
+                            </TableCell>
+                          </>
                         )}
                         <TableCell className="py-2.5 pr-3 pl-0">
                           <Button

Frontend/erp-system/app/dashboard/products/settings/page.tsx

@@ -12,12 +12,11 @@ import { Switch } from "@/components/ui/switch"
 import { toast } from "@/components/ui/toast"
 
 /**
- * Product Configuration (docs/11 §2.8; FR-MD-11) — the singleton feature gate.
+ * Product Configuration (docs/11 §2.8; FR-MD-11) - the singleton feature gate.
  *
- * `subcategoriesEnabled`/`brandsEnabled` are the only user-toggleable flags here and are
- * enforced by the server (an item write carrying a gated field gets 422 CONFIG_DISABLED).
- * `itemTypesEnabled` has no control on this screen but is still part of the record, so
- * every save round-trips its current value unchanged (the server rejects a partial body).
+ * Item types are the product-variant builder, while the other flags control whether item
+ * pricing, tracking and warranty-period fields are available when creating or editing an item.
+ * The server enforces the fields that are truly written to the item record.
  */
 export default function ProductSettingsPage() {
   const [config, setConfig] = useState<ProductConfig | null>(null)
@@ -38,17 +37,28 @@ export default function ProductSettingsPage() {
 
   useEffect(load, [])
 
-  async function toggle(flag: "subcategoriesEnabled" | "brandsEnabled", next: boolean) {
+  async function toggle(flag: keyof Pick<
+    ProductConfig,
+    | "subcategoriesEnabled"
+    | "brandsEnabled"
+    | "itemTypesEnabled"
+    | "sellingPricesEnabled"
+    | "serialNumbersEnabled"
+    | "batchListsEnabled"
+    | "warrantyPeriodsEnabled"
+  >, next: boolean) {
     if (!config) return
     setSaving(flag)
     try {
-      // All three flags are always sent — the server rejects a partial body (400), which
-      // is what stops an omitted flag from silently switching a feature off.
       const res = await productConfigApi.update(
         {
           subcategoriesEnabled: config.subcategoriesEnabled,
           brandsEnabled: config.brandsEnabled,
           itemTypesEnabled: config.itemTypesEnabled,
+          sellingPricesEnabled: config.sellingPricesEnabled,
+          serialNumbersEnabled: config.serialNumbersEnabled,
+          batchListsEnabled: config.batchListsEnabled,
+          warrantyPeriodsEnabled: config.warrantyPeriodsEnabled,
           [flag]: next,
         },
         etag ?? "",
@@ -58,7 +68,7 @@ export default function ProductSettingsPage() {
       toast.success("Configuration saved", `${LABELS[flag]} ${next ? "enabled" : "disabled"}.`)
     } catch (err) {
       toast.error("Could not save configuration", errorMessage(err))
-      load() // a 412 means someone else changed it — resync rather than retry blind
+      load()
     } finally {
       setSaving(null)
     }
@@ -79,7 +89,7 @@ export default function ProductSettingsPage() {
         <div className="rounded-lg border border-destructive/30 bg-destructive/5 p-5 text-base text-destructive">{error}</div>
       )}
 
-      {!error && !config && <Skeleton className="h-64 w-full" />}
+      {!error && !config && <Skeleton className="h-80 w-full" />}
 
       {!error && config && (
         <div className="flex flex-col gap-4 rounded-xl border p-6">
@@ -90,9 +100,49 @@ export default function ProductSettingsPage() {
           <div className="border-t" />
 
           <div className="grid grid-cols-1 gap-x-10 md:grid-cols-2">
+            <ToggleRow
+              label="Product variants"
+              description="Controls the variant builder on item create. Off hides the item-type section."
+              checked={config.itemTypesEnabled}
+              busy={saving === "itemTypesEnabled"}
+              onChange={(v) => toggle("itemTypesEnabled", v)}
+            />
+
+            <ToggleRow
+              label="Selling prices"
+              description="Controls the min, max and flat sale price fields on item create and edit."
+              checked={config.sellingPricesEnabled}
+              busy={saving === "sellingPricesEnabled"}
+              onChange={(v) => toggle("sellingPricesEnabled", v)}
+            />
+
+            <ToggleRow
+              label="Serial numbers"
+              description="Allows items to be created with Serial tracking."
+              checked={config.serialNumbersEnabled}
+              busy={saving === "serialNumbersEnabled"}
+              onChange={(v) => toggle("serialNumbersEnabled", v)}
+            />
+
+            <ToggleRow
+              label="Batch lists"
+              description="Allows items to be created with Batch tracking."
+              checked={config.batchListsEnabled}
+              busy={saving === "batchListsEnabled"}
+              onChange={(v) => toggle("batchListsEnabled", v)}
+            />
+
+            <ToggleRow
+              label="Warranty periods"
+              description="Allows warranty-tracked items to pick a coverage period."
+              checked={config.warrantyPeriodsEnabled}
+              busy={saving === "warrantyPeriodsEnabled"}
+              onChange={(v) => toggle("warrantyPeriodsEnabled", v)}
+            />
+
             <ToggleRow
               label="Subcategories"
-              description="Category hierarchy includes a subcategory level. Off ⇒ products attach directly to a category."
+              description="Category hierarchy includes a subcategory level. Off means products attach directly to a category."
               checked={config.subcategoriesEnabled}
               busy={saving === "subcategoriesEnabled"}
               onChange={(v) => toggle("subcategoriesEnabled", v)}
@@ -119,9 +169,16 @@ export default function ProductSettingsPage() {
   )
 }
 
-const LABELS: Record<string, string> = {
+const LABELS: Record<keyof ProductConfig, string> = {
   subcategoriesEnabled: "Subcategories",
   brandsEnabled: "Brands",
+  itemTypesEnabled: "Product variants",
+  sellingPricesEnabled: "Selling prices",
+  serialNumbersEnabled: "Serial numbers",
+  batchListsEnabled: "Batch lists",
+  warrantyPeriodsEnabled: "Warranty periods",
+  updatedAt: "Updated at",
+  updatedBy: "Updated by",
 }
 
 function ToggleRow({

Frontend/erp-system/app/dashboard/settings/notification-config/page.tsx

@@ -0,0 +1,214 @@
+"use client"
+
+import { useEffect, useMemo, useState } from "react"
+import { BellRing, Check, ShieldAlert } from "lucide-react"
+
+import { notificationConfigApi } from "@/lib/api/notification-config"
+import { errorMessage } from "@/lib/error-map"
+import { cn } from "@/lib/utils"
+import { NotificationChannel, NotificationConfig } from "@/types/notifications"
+
+import { Badge } from "@/components/ui/badge"
+import { Button } from "@/components/ui/button"
+import { Checkbox } from "@/components/ui/checkbox"
+import { Skeleton } from "@/components/ui/skeleton"
+import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from "@/components/ui/table"
+import { toast } from "@/components/ui/toast"
+
+const CHANNELS: { key: NotificationChannel; label: string }[] = [
+  { key: "Email", label: "Email" },
+  { key: "Sms", label: "SMS" },
+  { key: "InApp", label: "In-App" },
+]
+
+export default function NotificationConfigPage() {
+  const [config, setConfig] = useState<NotificationConfig | null>(null)
+  const [etag, setEtag] = useState<string | null>(null)
+  const [error, setError] = useState<string | null>(null)
+  const [saving, setSaving] = useState(false)
+
+  function load() {
+    setError(null)
+    notificationConfigApi
+      .get()
+      .then((res) => {
+        setConfig(res.data)
+        setEtag(res.etag)
+      })
+      .catch((err) => setError(errorMessage(err)))
+  }
+
+  useEffect(load, [])
+
+  const modules = config?.modules ?? []
+  const hasModules = modules.length > 0
+
+  const rows = useMemo(
+    () => modules.map((m) => ({
+      ...m,
+      enabledCount: [m.emailEnabled, m.smsEnabled, m.inAppEnabled].filter(Boolean).length,
+    })),
+    [modules]
+  )
+
+  function updateModule(moduleKey: string, channel: NotificationChannel, checked: boolean) {
+    setConfig((prev) => {
+      if (!prev) return prev
+      return {
+        ...prev,
+        modules: prev.modules.map((m) =>
+          m.moduleKey === moduleKey
+            ? {
+                ...m,
+                emailEnabled: channel === "Email" ? checked : m.emailEnabled,
+                smsEnabled: channel === "Sms" ? checked : m.smsEnabled,
+                inAppEnabled: channel === "InApp" ? checked : m.inAppEnabled,
+              }
+            : m
+        ),
+      }
+    })
+  }
+
+  async function handleSave() {
+    if (!config) return
+    setSaving(true)
+    try {
+      const res = await notificationConfigApi.update(
+        {
+          modules: config.modules.map((m) => ({
+            moduleKey: m.moduleKey,
+            emailEnabled: m.emailEnabled,
+            smsEnabled: m.smsEnabled,
+            inAppEnabled: m.inAppEnabled,
+          })),
+        },
+        etag ?? "",
+      )
+      setConfig(res.data)
+      setEtag(res.etag)
+      toast.success("Notification configuration saved")
+    } catch (err) {
+      const detail = errorMessage(err)
+      toast.error("Could not save notification configuration", detail)
+      if ((err as { code?: string })?.code === "CONCURRENCY_CONFLICT") {
+        load()
+      } else {
+        setError(detail)
+      }
+    } finally {
+      setSaving(false)
+    }
+  }
+
+  return (
+    <div className="flex flex-col gap-6">
+      <div className="flex flex-col gap-3 sm:flex-row sm:items-center sm:justify-between">
+        <div className="flex items-center gap-3">
+          <div className="flex size-11 shrink-0 items-center justify-center rounded-xl bg-primary/10">
+            <BellRing className="size-5 text-primary" />
+          </div>
+          <div>
+            <h1 className="text-2xl font-bold text-foreground">Notification Config</h1>
+            <p className="text-base text-muted-foreground">
+              Choose which channels each module can use. A module may use none, one, or many channels.
+            </p>
+          </div>
+        </div>
+        <Button size="lg" onClick={handleSave} disabled={saving || !config}>
+          <Check className="size-5" />
+          {saving ? "Saving…" : "Save changes"}
+        </Button>
+      </div>
+
+      {error && (
+        <div className="rounded-lg border border-destructive/30 bg-destructive/5 p-5 text-base text-destructive">{error}</div>
+      )}
+
+      {!error && !config && <Skeleton className="h-72 w-full" />}
+
+      {!error && config && (
+        <div className="flex flex-col gap-4 rounded-xl border p-5">
+          <div className="flex items-start gap-3 rounded-lg border border-primary/20 bg-primary/5 p-4">
+            <ShieldAlert className="mt-0.5 size-5 shrink-0 text-primary" />
+            <div className="flex flex-col gap-1">
+              <p className="text-sm font-medium text-foreground">
+                Empty selections are allowed.
+              </p>
+              <p className="text-sm text-muted-foreground">
+                If a module has no channels enabled, the notification resolver skips delivery for that module.
+              </p>
+            </div>
+          </div>
+
+          {!hasModules ? (
+            <div className="rounded-lg border border-dashed px-6 py-16 text-center text-muted-foreground">
+              No notification modules were discovered in the backend.
+            </div>
+          ) : (
+            <div className="overflow-x-auto">
+              <Table className="text-base">
+                <TableHeader>
+                  <TableRow>
+                    <TableHead className="h-12 px-3 text-sm">Module</TableHead>
+                    {CHANNELS.map((channel) => (
+                      <TableHead key={channel.key} className="h-12 px-3 text-sm text-center">
+                        {channel.label}
+                      </TableHead>
+                    ))}
+                    <TableHead className="h-12 px-3 text-sm text-center">Enabled</TableHead>
+                  </TableRow>
+                </TableHeader>
+                <TableBody>
+                  {rows.map((module) => (
+                    <TableRow key={module.moduleKey}>
+                      <TableCell className="px-3 py-4">
+                        <div className="flex flex-col gap-1">
+                          <span className="font-medium text-foreground">{module.label}</span>
+                          <span className="text-sm text-muted-foreground">{module.description}</span>
+                          <span className="text-xs text-muted-foreground">{module.moduleKey}</span>
+                        </div>
+                      </TableCell>
+                      <TableCell className="px-3 py-4 text-center">
+                        <Checkbox
+                          checked={module.emailEnabled}
+                          onCheckedChange={(checked) => updateModule(module.moduleKey, "Email", checked === true)}
+                          aria-label={`${module.label} email channel`}
+                        />
+                      </TableCell>
+                      <TableCell className="px-3 py-4 text-center">
+                        <Checkbox
+                          checked={module.smsEnabled}
+                          onCheckedChange={(checked) => updateModule(module.moduleKey, "Sms", checked === true)}
+                          aria-label={`${module.label} sms channel`}
+                        />
+                      </TableCell>
+                      <TableCell className="px-3 py-4 text-center">
+                        <Checkbox
+                          checked={module.inAppEnabled}
+                          onCheckedChange={(checked) => updateModule(module.moduleKey, "InApp", checked === true)}
+                          aria-label={`${module.label} in-app channel`}
+                        />
+                      </TableCell>
+                      <TableCell className="px-3 py-4 text-center">
+                        <Badge
+                          variant="outline"
+                          className={cn(
+                            "h-7 min-w-16 justify-center border-transparent px-2.5 text-sm",
+                            module.enabledCount > 0 ? "bg-success/10 text-success" : "bg-muted text-muted-foreground",
+                          )}
+                        >
+                          {module.enabledCount}
+                        </Badge>
+                      </TableCell>
+                    </TableRow>
+                  ))}
+                </TableBody>
+              </Table>
+            </div>
+          )}
+        </div>
+      )}
+    </div>
+  )
+}

Frontend/erp-system/app/dashboard/settings/page.tsx

@@ -1,5 +1,5 @@
 import Link from "next/link"
-import { Building2, ShieldCheck, SlidersHorizontal, Users } from "lucide-react"
+import { BellRing, Building2, ShieldCheck, SlidersHorizontal, Users } from "lucide-react"
 
 const cards = [
   {
@@ -14,6 +14,12 @@ const cards = [
     icon: Users,
     description: "Create users and assign their roles",
   },
+  {
+    title: "Notification Config",
+    href: "/dashboard/settings/notification-config",
+    icon: BellRing,
+    description: "Choose which channels each module can use",
+  },
   {
     title: "Product Configuration",
     href: "/dashboard/products/settings",

Frontend/erp-system/components/Layouts/Header.tsx

@@ -114,6 +114,7 @@ function titleFromPath(pathname: string) {
   if (pathname === "/dashboard/products/brands") return "Brands"
   if (pathname === "/dashboard/products/item-types") return "Item Types"
   if (pathname === "/dashboard/products/settings") return "Product Configuration"
+  if (pathname === "/dashboard/settings/notification-config") return "Notification Config"
   if (pathname === "/dashboard/settings/company-profile") return "Company Profile"
   if (/^\/dashboard\/products\/[^/]+$/.test(pathname)) return "Item"
 

Frontend/erp-system/lib/api/notification-config.ts

@@ -0,0 +1,13 @@
+import { apiRequest, apiRequestWithETag } from "@/lib/api-client"
+import { ApiResult } from "@/types/common"
+import { NotificationConfig, UpdateNotificationConfigRequest } from "@/types/notifications"
+
+export const notificationConfigApi = {
+  get(): Promise<ApiResult<NotificationConfig>> {
+    return apiRequestWithETag<NotificationConfig>("/notification-config")
+  },
+
+  update(request: UpdateNotificationConfigRequest, ifMatch: string): Promise<ApiResult<NotificationConfig>> {
+    return apiRequestWithETag<NotificationConfig>("/notification-config", { method: "PUT", body: request, ifMatch })
+  },
+}

Frontend/erp-system/lib/api/product-config.ts

@@ -1,9 +1,9 @@
-// Product configuration (docs/11-BACKEND-PHASE1.md §2.8; FR-MD-11). Singleton — no id.
+// Product configuration (docs/11-BACKEND-PHASE1.md §2.8; FR-MD-11). Singleton - no id.
 //
 // `subcategoriesEnabled`/`brandsEnabled` are enforced server-side: an item write carrying
 // a gated field while its flag is off returns 422 CONFIG_DISABLED. `itemTypesEnabled` is
-// ADVISORY — items hold no item-type reference, so there is nothing for the server to
-// reject; this frontend is what honours it by hiding the builder's type section.
+// ADVISORY - items hold no item-type reference, so there is nothing for the server to
+// reject; the frontend is what honours it by hiding the variant builder.
 import { apiRequest, apiRequestWithETag } from "@/lib/api-client"
 import { ApiResult } from "@/types/common"
 import { ProductConfig, UpdateProductConfigRequest } from "@/types/master-data"
@@ -13,7 +13,7 @@ export const productConfigApi = {
     return apiRequestWithETag<ProductConfig>("/product-config")
   },
 
-  /** All three flags are required; a partial body is a 400, never a silent disable. */
+  /** All flags are required; a partial body is a 400, never a silent disable. */
   update(request: UpdateProductConfigRequest, ifMatch: string): Promise<ApiResult<ProductConfig>> {
     return apiRequestWithETag<ProductConfig>("/product-config", { method: "PUT", body: request, ifMatch })
   },

Frontend/erp-system/types/master-data.ts

@@ -287,6 +287,10 @@ export interface ProductConfig {
   subcategoriesEnabled: boolean
   brandsEnabled: boolean
   itemTypesEnabled: boolean
+  sellingPricesEnabled: boolean
+  serialNumbersEnabled: boolean
+  batchListsEnabled: boolean
+  warrantyPeriodsEnabled: boolean
   updatedAt: string | null
   updatedBy: number | null
 }
@@ -296,4 +300,8 @@ export interface UpdateProductConfigRequest {
   subcategoriesEnabled: boolean
   brandsEnabled: boolean
   itemTypesEnabled: boolean
+  sellingPricesEnabled: boolean
+  serialNumbersEnabled: boolean
+  batchListsEnabled: boolean
+  warrantyPeriodsEnabled: boolean
 }

Frontend/erp-system/types/notifications.ts

@@ -0,0 +1,27 @@
+export type NotificationChannel = "Email" | "Sms" | "InApp"
+
+export interface NotificationModuleConfig {
+  moduleKey: string
+  label: string
+  description: string
+  emailEnabled: boolean
+  smsEnabled: boolean
+  inAppEnabled: boolean
+}
+
+export interface NotificationConfig {
+  modules: NotificationModuleConfig[]
+  updatedAt: string | null
+  updatedBy: number | null
+}
+
+export interface UpdateNotificationModuleRequest {
+  moduleKey: string
+  emailEnabled?: boolean | null
+  smsEnabled?: boolean | null
+  inAppEnabled?: boolean | null
+}
+
+export interface UpdateNotificationConfigRequest {
+  modules: UpdateNotificationModuleRequest[]
+}