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/DiscountShopCQ/Commands/PlaceOrder/PlaceOrderCommandHandler.cs

@@ -5,6 +5,8 @@ using CMSMicroservice.Domain.Entities.Payment;
 using CMSMicroservice.Domain.Enums;
 using MediatR;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
 
 namespace CMSMicroservice.Application.DiscountShopCQ.Commands.PlaceOrder;
 
@@ -12,13 +14,22 @@ public class PlaceOrderCommandHandler : IRequestHandler<PlaceOrderCommand, Place
 {
     private readonly IApplicationDbContext _context;
     private readonly IInventoryService _inventoryService;
+    private readonly IPaymentGatewayService _paymentGateway;
+    private readonly IConfiguration _configuration;
+    private readonly ILogger<PlaceOrderCommandHandler> _logger;
 
     public PlaceOrderCommandHandler(
         IApplicationDbContext context,
-        IInventoryService inventoryService)
+        IInventoryService inventoryService,
+        IPaymentGatewayService paymentGateway,
+        IConfiguration configuration,
+        ILogger<PlaceOrderCommandHandler> logger)
     {
         _context = context;
         _inventoryService = inventoryService;
+        _paymentGateway = paymentGateway;
+        _configuration = configuration;
+        _logger = logger;
     }
 
     public async Task<PlaceOrderResponseDto> Handle(PlaceOrderCommand request, CancellationToken cancellationToken)
@@ -172,15 +183,102 @@ public class PlaceOrderCommandHandler : IRequestHandler<PlaceOrderCommand, Place
 
         await _context.SaveChangesAsync(cancellationToken);
 
+        // اگر مبلغ درگاه > ۰ باشد، باید به درگاه پرداخت متصل شویم
+        string? paymentUrl = null;
+
+        if (finalGatewayAmount > 0)
+        {
+            try
+            {
+                // آدرس callback — زرین‌پال بعد از پرداخت کاربر را به اینجا هدایت می‌کند
+                var cmsBaseUrl = _configuration["CmsBaseUrl"] ?? "https://localhost:32846";
+                var callbackUrl = $"{cmsBaseUrl}/api/payment/discount-order/callback?orderId={order.Id}";
+
+                // درخواست به درگاه
+                var paymentResult = await _paymentGateway.InitiatePaymentAsync(new PaymentRequest
+                {
+                    Amount = finalGatewayAmount,
+                    UserId = request.UserId,
+                    Description = $"فروشگاه تخفیفی - سفارش #{order.Id}",
+                    CallbackUrl = callbackUrl
+                }, cancellationToken);
+
+                if (paymentResult.IsSuccess && !string.IsNullOrEmpty(paymentResult.GatewayUrl))
+                {
+                    // ذخیره Authority/RefId در تراکنش برای verify بعدی
+                    transaction.RefId = paymentResult.RefId;
+                    await _context.SaveChangesAsync(cancellationToken);
+
+                    paymentUrl = paymentResult.GatewayUrl;
+                    _logger.LogInformation(
+                        "Payment gateway initiated for DiscountOrder #{OrderId}: RefId={RefId}, Url={Url}",
+                        order.Id, paymentResult.RefId, paymentResult.GatewayUrl);
+                }
+                else
+                {
+                    _logger.LogError(
+                        "Payment gateway initiation failed for DiscountOrder #{OrderId}: {Error}",
+                        order.Id, paymentResult.ErrorMessage);
+
+                    return new PlaceOrderResponseDto
+                    {
+                        Success = false,
+                        Message = $"خطا در اتصال به درگاه پرداخت: {paymentResult.ErrorMessage}",
+                        OrderId = order.Id
+                    };
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Payment gateway exception for DiscountOrder #{OrderId}", order.Id);
+                return new PlaceOrderResponseDto
+                {
+                    Success = false,
+                    Message = $"خطا در اتصال به درگاه پرداخت: {ex.Message}",
+                    OrderId = order.Id
+                };
+            }
+        }
+        else
+        {
+            // اگر کل مبلغ از کیف تخفیفی پرداخت شد — مستقیماً تکمیل شود
+            transaction.PaymentStatus = PaymentStatus.Success;
+            transaction.PaymentDate = DateTime.Now;
+            order.PaymentStatus = PaymentStatus.Success;
+            order.PaymentDate = DateTime.Now;
+            order.DeliveryStatus = DeliveryStatus.InTransit;
+
+            var walletForDeduct = await _context.UserWallets
+                .FirstOrDefaultAsync(w => w.UserId == request.UserId, cancellationToken);
+            if (walletForDeduct != null)
+                walletForDeduct.DiscountBalance -= actualDiscountBalanceUsed;
+
+            foreach (var cartItem in cartItems)
+            {
+                await _inventoryService.ConfirmSaleAsync(
+                    cartItem.ProductId, ProductType.DiscountProduct,
+                    cartItem.Count, order.Id, cancellationToken);
+                cartItem.Product.SaleCount += cartItem.Count;
+            }
+
+            await _context.SaveChangesAsync(cancellationToken);
+            _logger.LogInformation(
+                "DiscountOrder #{OrderId} fully paid via discount balance ({Amount} T)",
+                order.Id, actualDiscountBalanceUsed);
+        }
+
         return new PlaceOrderResponseDto
         {
             Success = true,
-            Message = "سفارش ایجاد شد. لطفا پرداخت را تکمیل کنید",
+            Message = finalGatewayAmount > 0
+                ? "سفارش ایجاد شد. در حال انتقال به درگاه پرداخت..."
+                : "سفارش با موفقیت ثبت و پرداخت شد",
             OrderId = order.Id,
             TransactionId = transaction.Id,
             TotalAmount = totalAmount,
             DiscountBalanceUsed = actualDiscountBalanceUsed,
-            GatewayAmountRequired = finalGatewayAmount
+            GatewayAmountRequired = finalGatewayAmount,
+            PaymentUrl = paymentUrl
         };
     }
 }