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/Common/Behaviours/LoggingBehaviour.cs

@@ -18,7 +18,10 @@ public class LoggingBehaviour<TRequest> : IRequestPreProcessor<TRequest> where T
     {
         var requestName = typeof(TRequest).Name;
         var userId = _currentUserService.UserId ?? string.Empty;
-        _logger.LogInformation("Request: {Name} {@UserId} {@Request}",
-            requestName, userId, request);
+        var safeLog = request?.ToString() ?? "";
+        if (safeLog.Length > 2000)
+            safeLog = safeLog[..2000] + "... [TRUNCATED]";
+        _logger.LogInformation("Request: {Name} {UserId} {Request}",
+            requestName, userId, safeLog);
     }
 }

src/CMSMicroservice.Application/Common/Behaviours/PerformanceBehaviour.cs

@@ -1,16 +1,20 @@
 using System.Diagnostics;
+using System.Text.RegularExpressions;
 using MediatR;
 using Microsoft.Extensions.Logging;
 
 namespace CMSMicroservice.Application.Common.Behaviours;
 
-public class PerformanceBehaviour<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
+public partial class PerformanceBehaviour<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
     where TRequest : IRequest<TResponse>
 {
     private readonly Stopwatch _timer;
     private readonly ILogger<TRequest> _logger;
     private readonly ICurrentUserService _currentUserService;
 
+    [GeneratedRegex(@"ImageFile(?:Bytes|Mime|FileName)|ImageFile|File", RegexOptions.None)]
+    private static partial Regex BinaryPropertyPattern();
+
     public PerformanceBehaviour(ILogger<TRequest> logger, ICurrentUserService currentUserService)
     {
         _timer = new Stopwatch();
@@ -33,11 +37,20 @@ public class PerformanceBehaviour<TRequest, TResponse> : IPipelineBehavior<TRequ
         {
             var requestName = typeof(TRequest).Name;
             var userId = _currentUserService.UserId ?? string.Empty;
+            var safeLog = SanitizeForLog(request);
 
-            _logger.LogWarning("Long Running Request: {Name} ({ElapsedMilliseconds} milliseconds) {@UserId} {@Request}",
-                requestName, elapsedMilliseconds, userId, request);
+            _logger.LogWarning("Long Running Request: {Name} ({ElapsedMilliseconds} milliseconds) {UserId} {Request}",
+                requestName, elapsedMilliseconds, userId, safeLog);
         }
 
         return response;
     }
+
+    private static string SanitizeForLog(TRequest request)
+    {
+        var text = request?.ToString() ?? "";
+        if (text.Length > 2000)
+            return text[..2000] + "... [TRUNCATED]";
+        return text;
+    }
 }

src/CMSMicroservice.Application/Common/Behaviours/UnhandledExceptionBehaviour.cs

@@ -22,8 +22,11 @@ public class UnhandledExceptionBehaviour<TRequest, TResponse> : IPipelineBehavio
         catch (Exception ex)
         {
             var requestName = typeof(TRequest).Name;
+            var safeLog = request?.ToString() ?? "";
+            if (safeLog.Length > 2000)
+                safeLog = safeLog[..2000] + "... [TRUNCATED]";
 
-            _logger.LogError(ex, "Request: Unhandled Exception for Request {Name} {@Request}", requestName, request);
+            _logger.LogError(ex, "Request: Unhandled Exception for Request {Name} {Request}", requestName, safeLog);
 
             throw;
         }