feat(library): ignore a release (do-not-monitor)

Add MonitoredRelease.ignored (migration add_release_ignored). The monitor's
enqueue_due skips ignored releases, and they drop off the Wanted list —
independent of `monitored`, so auto-monitor-future can't silently re-grab
an album the user chose to ignore.

- Worker enqueue_due: AND NOT mr.ignored.
- /api/releases/[id] PATCH now accepts `ignored`; /api/wanted filters it out;
  artist detail exposes `ignored`.
- UI: Ignore button on Wanted rows; discography shows an "Ignored" badge with
  an Ignore/Un-ignore toggle (monitor + search disabled while ignored).

Worker + web tests added.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/app/api/artists/[id]/route.ts

@@ -27,6 +27,7 @@ export async function GET(request: Request, { params }: { params: Promise<{ id:
       secondaryTypes: r.secondaryTypes,
       firstReleaseDate: r.firstReleaseDate,
       monitored: r.monitored,
+      ignored: r.ignored,
       state: r.state,
       currentQualityClass: r.currentQualityClass,
     })),