feature: CMS Opus status surfaces — backfill missing-N badge + upload Post-Processing phase (18.6)

DeepDrftManager/Services/ICmsTrackService.cs

@@ -161,6 +161,14 @@ public interface ICmsTrackService
     /// </summary>
     Task<ResultContainer<OpusBackfillResult>> BackfillOpusAsync(CancellationToken ct = default);
 
+    /// <summary>
+    /// Fetch per-track Opus derive status from <c>GET api/track/opus-status</c> (Phase 18.6) for the CMS
+    /// Post-Processing surfaces. Unpaged — the admin catalogue is small. Each row's <c>HasOpus</c> is true only
+    /// when the track carries a complete Opus artifact (audio + sidecar). Drives the Backfill-Opus "missing N"
+    /// badge and the post-upload Post-Processing poll. Idempotent read — safe to poll on an interval.
+    /// </summary>
+    Task<ResultContainer<OpusStatusDto[]>> GetOpusStatusAsync(CancellationToken ct = default);
+
     /// <summary>Returns all releases with track counts from GET api/track/albums.</summary>
     Task<ResultContainer<List<ReleaseDto>>> GetReleasesAsync(CancellationToken ct = default);