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/UserService.cs

@@ -34,7 +34,7 @@ public class UserService : UserContract.UserContractBase
     private readonly IApplicationDbContext _context;
     private readonly ICurrentUserService _currentUserService;
     private readonly IHashService _hashService;
-    private readonly IFileManagementService _fileManagementService;
+    private readonly CMSMicroservice.Application.Common.FileManager.IFileManager _fileManager;
 
     public UserService(
         IDispatchRequestToCQRS dispatchRequestToCQRS, 
@@ -42,14 +42,14 @@ public class UserService : UserContract.UserContractBase
         IApplicationDbContext context,
         ICurrentUserService currentUserService,
         IHashService hashService,
-        IFileManagementService fileManagementService)
+        CMSMicroservice.Application.Common.FileManager.IFileManager fileManager)
     {
         _dispatchRequestToCQRS = dispatchRequestToCQRS;
         _sender = sender;
         _context = context;
         _currentUserService = currentUserService;
         _hashService = hashService;
-        _fileManagementService = fileManagementService;
+        _fileManager = fileManager;
     }
     public override async Task<CreateNewUserResponse> CreateNewUser(CreateNewUserRequest request, ServerCallContext context)
     {
@@ -65,6 +65,10 @@ public class UserService : UserContract.UserContractBase
     }
     public override async Task<GetUserResponse> GetUser(GetUserRequest request, ServerCallContext context)
     {
+        // اگر Id ارسال نشده، از JWT بخون (برای کلاینت مشتری)
+        if (request.Id == 0)
+            request.Id = GetCurrentUserId();
+
         return await _dispatchRequestToCQRS.Handle<GetUserRequest, GetUserQuery, GetUserResponse>(request, context);
     }
     public override async Task<GetAllUserByFilterResponse> GetAllUserByFilter(GetAllUserByFilterRequest request, ServerCallContext context)
@@ -335,15 +339,28 @@ public class UserService : UserContract.UserContractBase
         if (user == null)
             throw new RpcException(new Status(StatusCode.NotFound, "کاربر یافت نشد"));
         
-        // Upload to FMS
+        // Upload to local file manager
         var fileBytes = request.FileData.ToByteArray();
         var fileName = $"avatar_{userId}_{DateTime.UtcNow.Ticks}";
         var mime = request.FileMimeType ?? "image/jpeg";
         
-        var avatarUrl = await _fileManagementService.UploadFileAsync(
-            "Avatars", fileBytes, mime, fileName, context.CancellationToken);
-        
-        if (string.IsNullOrEmpty(avatarUrl))
+        try
+        {
+            var result = await _fileManager.UploadImageAsync(
+                "Avatars", fileBytes, mime, fileName, context.CancellationToken);
+            
+            // Update user avatar path in DB
+            user.AvatarPath = result.Main.Path;
+            await _context.SaveChangesAsync(context.CancellationToken);
+            
+            return new UploadCustomerAvatarResponse
+            {
+                Success = true,
+                Message = "تصویر پروفایل با موفقیت آپلود شد",
+                AvatarUrl = result.Main.Path
+            };
+        }
+        catch (Exception ex)
         {
             return new UploadCustomerAvatarResponse
             {
@@ -351,17 +368,6 @@ public class UserService : UserContract.UserContractBase
                 Message = "خطا در آپلود فایل. لطفاً مجدد تلاش کنید"
             };
         }
-        
-        // Update user avatar path in DB
-        user.AvatarPath = avatarUrl;
-        await _context.SaveChangesAsync(context.CancellationToken);
-        
-        return new UploadCustomerAvatarResponse
-        {
-            Success = true,
-            Message = "تصویر پروفایل با موفقیت آپلود شد",
-            AvatarUrl = avatarUrl
-        };
     }
 
     public override async Task<GetCustomerSettingsResponse> GetCustomerSettings(GetCustomerSettingsRequest request, ServerCallContext context)