CMS Phase 9 Wave 3: Release Archive tab, medium selector, Session/Mix browsers

Renames Genre tab to Release Archive with switch-free medium card group
(Enum.GetValues-driven). Adds MediumFields single dispatch + CutFields/SessionFields/
MixFields per-medium sections embedded by all five upload/edit forms. BatchUpload
enforces single-track invariant for Session/Mix. Adds CmsSessionBrowser (hero-image
upload) and CmsMixBrowser (waveform status + per-row Generate trigger).
ICmsReleaseService/CmsReleaseService wraps api/release endpoints.
Note: medium selector is forward-compat only — API write path pending.

DeepDrftManager/Services/ICmsTrackService.cs

@@ -18,6 +18,10 @@ public interface ICmsTrackService
     /// orphan is handled and logged server-side; here it surfaces as a failed result.
     /// <paramref name="originalFileName"/> is the browser's filename, captured at upload time and
     /// stored as metadata; it is not user-editable afterwards.
+    /// <paramref name="medium"/> sets the parent release's <see cref="ReleaseMedium"/>. NOTE: the
+    /// current <c>POST api/track/upload</c> endpoint has no <c>medium</c> form field, so the value is
+    /// sent forward-compatibly and ignored server-side until the API binds it (Cut is the server
+    /// default). Wiring the selector through here keeps the CMS ready for that API change.
     /// </summary>
     Task<ResultContainer<TrackDto>> UploadTrackAsync(
         Stream wavStream,
@@ -32,6 +36,7 @@ public interface ICmsTrackService
         long createdByUserId,
         ReleaseType releaseType,
         int trackNumber,
+        ReleaseMedium medium = ReleaseMedium.Cut,
         CancellationToken ct = default);
 
     /// <summary>