feat: add vendor optional fields and configuration hooks

- Implemented VendorOptionalFields component to handle optional vendor details (mobile, email, address) with validation.
- Created useCustomerConfig hook to load optional customer field settings from Sales configuration.
- Developed useProcurementConfig hook to manage Procurement configuration flags.
- Introduced accessConfigApi for managing access configuration settings.
- Added openingBalancesApi for handling opening balances operations.
- Created procurementConfigApi for managing procurement configuration settings.
- Implemented nav-routes for permission-based routing.
- Developed PDF generation for purchase orders with dynamic vendor and item details.
- Added purchase-order tax helpers for tax calculations and formatting.
- Defined types for opening balances and related operations.

Backend/ERPCore/Program.cs

@@ -28,7 +28,12 @@ builder.Host.UseSerilog((ctx, cfg) => cfg
     .WriteTo.File("logs/erpcore-.log", rollingInterval: RollingInterval.Day));
 
 // Controllers + JSON: serialize enums as their string names (docs/11 §8, camelCase).
-builder.Services.AddControllers(o => o.Filters.Add<ERPCore.Infra.Filters.LowStockAlertFilter>())
+builder.Services.AddControllers(o =>
+    {
+        o.Filters.Add<ERPCore.Infra.Filters.LowStockAlertFilter>();
+        // CSRF double-submit check on every mutating, cookie-authenticated endpoint (docs/02-SECURITY.md §B.2).
+        o.Filters.Add<ERPCore.Infra.Auth.CsrfProtectionFilter>();
+    })
     .AddJsonOptions(o => o.JsonSerializerOptions.Converters.Add(new JsonStringEnumConverter()));
 
 // EF Core + MariaDB (Pomelo). The server version is pinned explicitly rather than using
@@ -119,6 +124,10 @@ builder.Services.AddScoped<IProductConfigService, ProductConfigService>();
 builder.Services.AddScoped<IBranchConfigService, BranchConfigService>();
 builder.Services.AddScoped<ISalesConfigService, SalesConfigService>();
 builder.Services.AddScoped<IGrnConfigService, GrnConfigService>();
+builder.Services.AddScoped<IProcurementConfigService, ProcurementConfigService>();
+builder.Services.AddScoped<IAccessConfigService, AccessConfigService>();
+builder.Services.AddScoped<IOpeningBalanceService, OpeningBalanceService>();
+builder.Services.AddScoped<IOpeningStockService, OpeningStockService>();
 builder.Services.AddScoped<IGlAccountConfigService, GlAccountConfigService>();
 builder.Services.AddScoped<IBranchAccessService, BranchAccessService>();
 builder.Services.AddSingleton<INotificationModuleCatalog, NotificationModuleCatalog>();