feat: CMS cover-art upload on track edit page

DeepDrftManager/Services/ICmsTrackService.cs

@@ -50,13 +50,25 @@ public interface ICmsTrackService
     /// </summary>
     Task<ResultContainer<TrackDto?>> GetByIdAsync(long id, CancellationToken ct = default);
 
+    /// <summary>
+    /// Upload a cover-art image to the images vault via <c>POST api/image/upload</c>.
+    /// Returns the generated entry key on success. Maps a 400 to a validation failure message.
+    /// </summary>
+    Task<ResultContainer<string>> UploadImageAsync(
+        Stream imageStream,
+        string fileName,
+        string contentType,
+        CancellationToken ct = default);
+
     /// <summary>
     /// Update a track's metadata via <c>PUT api/track/meta/{id}</c>. EntryKey is immutable and
-    /// not part of the update.
+    /// not part of the update. <paramref name="imagePath"/> is tri-state: <c>null</c> leaves the
+    /// cover art unchanged, <c>""</c> clears it, and any other value sets it.
     /// </summary>
     Task<Result> UpdateAsync(
         long id, string trackName, string artist,
         string? album, string? genre, DateOnly? releaseDate,
+        string? imagePath = null,
         CancellationToken ct = default);
 
     /// <summary>