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/prisma/schema.prisma

@@ -126,6 +126,10 @@ model MonitoredRelease {
   secondaryTypes      String[]
   firstReleaseDate    String?
   monitored           Boolean               @default(false)
+  // User marked this release "do not monitor" — the monitor skips it (never enqueued as
+  // wanted/upgrade) and it drops off the Wanted list, independent of `monitored`, so
+  // auto-monitor-future can't silently re-grab it. Reversible from the discography page.
+  ignored             Boolean               @default(false)
   state               MonitoredReleaseState @default(wanted)
   currentQualityClass Int?
   firstGrabbedAt      DateTime?