feat: Implement file management and authorization features

- Add RequiresPermissionAttribute for gRPC method access control.
- Create IFileManagementService interface for file upload and management.
- Implement AddProductImageCommand and handler for adding product images.
- Implement CreateNewProductsCommand and handler for creating new products with image uploads.
- Implement DeleteProductsCommand and handler for deleting products and their associations.
- Implement RemoveProductImageCommand and handler for removing product images from galleries.
- Implement UpdateProductsCommand and handler for updating product details and images.
- Create GetProductGalleryQuery and handler for retrieving product galleries.
- Implement PermissionService for role-based access control using JWT claims.
- Implement FileManagementService for handling file uploads and image optimization.
- Define gRPC service and messages for file management in fms.proto.
- Add FluentValidation for request validation in various commands.
- Create PermissionInterceptor for enforcing permissions on gRPC methods.

src/CMSMicroservice.Protobuf/Protos/inventory.proto

@@ -270,6 +270,8 @@ message InventoryItemDto {
     string product_title = 15;
     int64 product_price = 16;
     google.protobuf.Timestamp created = 17;
+    // آیا موجودی کم است (موجودی قابل فروش کمتر از حد هشدار)
+    bool is_low_stock = 18;
 }
 
 message GetInventoryItemRequest {