Refactor sales pipeline: ShopPO, Invoice, SysConfig models

Major refactor replacing Sale/Order with ShopPO → Invoice → LoadingSheet flow. Removed legacy Sale/Order models and features; introduced ShopPO, ShopPOItem, Invoice, LoadingSheetOrder, and SysConfig models. Updated related entities, enums, repositories, and controllers. Added new migrations for schema changes and system config. Overhauled business logic and DI registrations. Updated documentation with migration plan.

Distribution/Features/Store/IStoreRepository.cs

@@ -12,5 +12,5 @@ public interface IStoreRepository
     Task AddAsync(Models.Store entity);
     void Update(Models.Store entity);
     void Remove(Models.Store entity);
-    Task<List<Models.Order>> GetOrdersForDashboardAsync(Guid storeId, DateTime periodStart, DateTime periodEndExclusive);
+    Task<List<Models.ShopPO>> GetOrdersForDashboardAsync(Guid storeId, DateTime periodStart, DateTime periodEndExclusive);
 }

Distribution/Features/Store/StoreRepository.cs

@@ -48,8 +48,8 @@ public class StoreRepository(AppDBContext context) : IStoreRepository
         context.Stores.Update(entity);
     }
 
-    public async Task<List<Models.Order>> GetOrdersForDashboardAsync(Guid storeId, DateTime periodStart, DateTime periodEndExclusive) =>
-        await context.Orders
-            .Where(o => o.FK_StoreId == storeId && o.IsActive && o.OrderDate >= periodStart && o.OrderDate < periodEndExclusive)
+    public async Task<List<Models.ShopPO>> GetOrdersForDashboardAsync(Guid storeId, DateTime periodStart, DateTime periodEndExclusive) =>
+        await context.ShopPOs
+            .Where(o => o.FK_StoreId == storeId && o.IsActive && o.CreatedAt >= periodStart && o.CreatedAt < periodEndExclusive)
             .ToListAsync();
 }

Distribution/Features/Store/StoreService.cs

@@ -268,6 +268,6 @@ public class StoreService(IStoreRepository repo, IUnitOfWork uow, ICurrentUserSe
             periodStart.ToString("yyyy-MM"),
             orders.Count,
             orders.Sum(o => o.TotalAmount),
-            orders.Count == 0 ? null : orders.Max(o => o.OrderDate));
+            orders.Count == 0 ? null : orders.Max(o => o.CreatedAt));
     }
 }