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

DeepDrftModels/DTOs/OpusStatusDto.cs

@@ -0,0 +1,19 @@
+namespace DeepDrftModels.DTOs;
+
+/// <summary>
+/// Per-track Opus derive status for the CMS Post-Processing surfaces (Phase 18.6). Mirrors
+/// <see cref="WaveformStatusDto"/>: one row per track, flagging whether the track already carries a
+/// <strong>complete</strong> Opus artifact. "Complete" means BOTH the Opus audio bytes AND the seek/setup
+/// sidecar are present in the <c>track-opus</c> vault — a half-derived track (audio without sidecar) is
+/// unseekable and counts as missing, so the Backfill-Opus pass re-derives it. <see cref="EntryKey"/> is the
+/// vault key the per-track enqueue trigger and the polling Post-Processing affordance key on.
+/// </summary>
+public class OpusStatusDto
+{
+    public long TrackId { get; set; }
+    public string EntryKey { get; set; } = string.Empty;
+    public string TrackName { get; set; } = string.Empty;
+
+    /// <summary>True only when both the Opus audio and the seek/setup sidecar are stored (a complete derive).</summary>
+    public bool HasOpus { get; set; }
+}