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.WebApi/Services/DiscountShoppingCartService.cs

@@ -1,44 +1,111 @@
 using CMSMicroservice.Protobuf.Protos.DiscountShoppingCart;
 using CMSMicroservice.WebApi.Common.Services;
+using CMSMicroservice.Application.Common.Interfaces;
 using CMSMicroservice.Application.DiscountShopCQ.Commands.AddToCart;
 using CMSMicroservice.Application.DiscountShopCQ.Commands.RemoveFromCart;
 using CMSMicroservice.Application.DiscountShopCQ.Commands.UpdateCartItemCount;
 using CMSMicroservice.Application.DiscountShopCQ.Commands.ClearCart;
 using CMSMicroservice.Application.DiscountShopCQ.Queries.GetUserCart;
+using Grpc.Core;
+using Mapster;
+using MediatR;
 
 namespace CMSMicroservice.WebApi.Services;
 
 public class DiscountShoppingCartService : DiscountShoppingCartContract.DiscountShoppingCartContractBase
 {
     private readonly IDispatchRequestToCQRS _dispatchRequestToCQRS;
+    private readonly ISender _sender;
+    private readonly ICurrentUserService _currentUserService;
 
-    public DiscountShoppingCartService(IDispatchRequestToCQRS dispatchRequestToCQRS)
+    public DiscountShoppingCartService(
+        IDispatchRequestToCQRS dispatchRequestToCQRS,
+        ISender sender,
+        ICurrentUserService currentUserService)
     {
         _dispatchRequestToCQRS = dispatchRequestToCQRS;
+        _sender = sender;
+        _currentUserService = currentUserService;
+    }
+
+    private long GetCurrentUserId()
+    {
+        if (long.TryParse(_currentUserService.UserId, out var uid) && uid > 0)
+            return uid;
+        throw new RpcException(new Status(StatusCode.Unauthenticated, "کاربر احراز هویت نشده است"));
     }
 
     public override async Task<AddToCartResponse> AddToCart(AddToCartRequest request, ServerCallContext context)
     {
-        return await _dispatchRequestToCQRS.Handle<AddToCartRequest, AddToCartCommand, AddToCartResponse>(request, context);
+        var command = new AddToCartCommand
+        {
+            UserId = GetCurrentUserId(),
+            ProductId = request.ProductId,
+            Count = request.Count
+        };
+        var result = await _sender.Send(command, context.CancellationToken);
+        return result.Adapt<AddToCartResponse>();
     }
 
     public override async Task<RemoveFromCartResponse> RemoveFromCart(RemoveFromCartRequest request, ServerCallContext context)
     {
-        return await _dispatchRequestToCQRS.Handle<RemoveFromCartRequest, RemoveFromCartCommand, RemoveFromCartResponse>(request, context);
+        var command = new RemoveFromCartCommand
+        {
+            UserId = GetCurrentUserId(),
+            ProductId = request.ProductId
+        };
+        var result = await _sender.Send(command, context.CancellationToken);
+        return result.Adapt<RemoveFromCartResponse>();
     }
 
     public override async Task<UpdateCartItemCountResponse> UpdateCartItemCount(UpdateCartItemCountRequest request, ServerCallContext context)
     {
-        return await _dispatchRequestToCQRS.Handle<UpdateCartItemCountRequest, UpdateCartItemCountCommand, UpdateCartItemCountResponse>(request, context);
+        var command = new UpdateCartItemCountCommand
+        {
+            UserId = GetCurrentUserId(),
+            ProductId = request.ProductId,
+            NewCount = request.NewCount
+        };
+        var result = await _sender.Send(command, context.CancellationToken);
+        return result.Adapt<UpdateCartItemCountResponse>();
     }
 
     public override async Task<GetUserCartResponse> GetUserCart(GetUserCartRequest request, ServerCallContext context)
     {
-        return await _dispatchRequestToCQRS.Handle<GetUserCartRequest, GetUserCartQuery, GetUserCartResponse>(request, context);
+        var query = new GetUserCartQuery { UserId = GetCurrentUserId() };
+        var cart = await _sender.Send(query, context.CancellationToken);
+
+        var response = new GetUserCartResponse
+        {
+            TotalPrice = cart.TotalAmount,
+            TotalDiscountAmount = cart.MaxDiscountAmount,
+            FinalPrice = cart.MinPayableAmount
+        };
+
+        foreach (var item in cart.Items)
+        {
+            response.Items.Add(new CMSMicroservice.Protobuf.Protos.DiscountShoppingCart.CartItemDto
+            {
+                ProductId = item.ProductId,
+                ProductTitle = item.ProductTitle ?? string.Empty,
+                ProductImagePath = item.ProductImagePath ?? string.Empty,
+                UnitPrice = item.UnitPrice,
+                MaxDiscountPercent = item.MaxDiscountPercent,
+                Count = item.Count,
+                TotalPrice = item.SubTotal,
+                DiscountAmount = item.MaxDiscountAmount,
+                FinalPrice = item.MinPayable,
+                ProductRemainingCount = item.RemainingStock
+            });
+        }
+
+        return response;
     }
 
     public override async Task<Empty> ClearCart(ClearCartRequest request, ServerCallContext context)
     {
-        return await _dispatchRequestToCQRS.Handle<ClearCartRequest, ClearCartCommand>(request, context);
+        var command = new ClearCartCommand { UserId = GetCurrentUserId() };
+        await _sender.Send(command, context.CancellationToken);
+        return new Empty();
     }
 }