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.Application/Common/Interfaces/IFileManagementService.cs

@@ -0,0 +1,37 @@
+namespace CMSMicroservice.Application.Common.Interfaces;
+
+/// <summary>
+/// Service for uploading files to FMS (File Management Service)
+/// </summary>
+public interface IFileManagementService
+{
+    /// <summary>
+    /// Uploads a file to FMS and returns the stored file path
+    /// </summary>
+    /// <param name="directory">Target directory path (e.g. "Images/Products")</param>
+    /// <param name="fileBytes">Raw file bytes</param>
+    /// <param name="mime">MIME type (e.g. "image/jpeg")</param>
+    /// <param name="fileName">Original file name</param>
+    /// <param name="cancellationToken">Cancellation token</param>
+    /// <returns>The stored file path returned by FMS, or null if upload failed</returns>
+    Task<string?> UploadFileAsync(string directory, byte[] fileBytes, string mime, string? fileName, CancellationToken cancellationToken = default);
+    
+    /// <summary>
+    /// Uploads an image to FMS with optimization (resize + compress)
+    /// Returns both main image path and thumbnail path
+    /// </summary>
+    /// <param name="directory">Target directory path (e.g. "Images/Products")</param>
+    /// <param name="fileBytes">Raw image bytes</param>
+    /// <param name="mime">MIME type (e.g. "image/jpeg")</param>
+    /// <param name="fileName">Original file name</param>
+    /// <param name="cancellationToken">Cancellation token</param>
+    /// <returns>Tuple of (mainImagePath, thumbnailPath), either can be null if upload failed</returns>
+    Task<(string? MainImagePath, string? ThumbnailPath)> UploadImageWithThumbnailAsync(
+        string directory, byte[] fileBytes, string mime, string? fileName, 
+        CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Deletes a file from FMS by its ID
+    /// </summary>
+    Task<bool> DeleteFileAsync(long fileId, CancellationToken cancellationToken = default);
+}