feat: integrate PYMS payment gateway, add blog/sitepage/image services, local file manager

Payment Gateway:
- Add PYMSPaymentService: IPaymentGatewayService via gRPC to PYMS microservice
- Add ZarinPalPaymentService: direct ZarinPal integration (backup)
- Register 'pyms' payment provider in DI ConfigureServices
- Add PYMS proto files (pyms_transaction.proto, pyms_public_messages.proto)
- Fix VerifyDiscountWalletCharge: pass 'OK' as status instead of Authority
- Update appsettings: PaymentProvider=pyms, sandbox mode, merchant ID

Blog System:
- Add BlogCategory, BlogPost, BlogPostImage entities and CQRS
- Add proto files and gRPC services for blog management
- Add Mapster profiles for blog responses

Content Management:
- Add SitePage entity and CQRS for static pages
- Add proto and gRPC service for site pages

Image/File Management:
- Add LocalFileManager with disk storage + base64 serving + FMS fallback
- Add ImagePathResolverInterceptor for gRPC responses
- Add ImageResolverService for explicit image resolution
- Add UploadsController for public file serving with FMS fallback
- Add PaymentCallbackController for discount order payment callbacks

Database:
- Add blog and content entity migrations
- Remove ImagePath MaxLength constraints
- Remove old FileManagementService (replaced by LocalFileManager)

src/CMSMicroservice.Application/CategoryCQ/Queries/GetAllCategoryByFilter/GetAllCategoryByFilterQueryHandler.cs

@@ -31,7 +31,18 @@ public class GetAllCategoryByFilterQueryHandler : IRequestHandler<GetAllCategory
         {
             MetaData = await query.GetMetaData(request.PaginationState, cancellationToken),
             Models = await query.PaginatedListAsync(paginationState: request.PaginationState)
-                .ProjectToType<GetAllCategoryByFilterResponseModel>().ToListAsync(cancellationToken)
+                .Select(x => new GetAllCategoryByFilterResponseModel
+                {
+                    Id = x.Id,
+                    Name = x.Name,
+                    Title = x.Title,
+                    Description = x.Description,
+                    ImagePath = x.ImagePath,
+                    ParentId = x.ParentId,
+                    IsActive = x.IsActive,
+                    SortOrder = x.SortOrder,
+                    ProductCount = x.ProductCategories.Count
+                }).ToListAsync(cancellationToken)
         };        
     }
 }

src/CMSMicroservice.Application/CategoryCQ/Queries/GetAllCategoryByFilter/GetAllCategoryByFilterResponseDto.cs

@@ -24,4 +24,6 @@ public class GetAllCategoryByFilterResponseDto
     public bool IsActive { get; set; }
     //ترتیب نمایش 
     public int SortOrder { get; set; }
+    //تعداد محصولات 
+    public int ProductCount { get; set; }
 }