feat(identity): lazy TMDB lookup and bounded identity pool (DEC-1)

RSS/list releases that match no subscription or local work no longer hit
TMDB or open a pending item; they go to the identity pool as `unmatched`.
TMDB is queried only on a local alias hit, a published new-title rule whose
prefilter passes, manual/Agent retry, search results, or when the new
setting identity.eagerTmdbLookup (default off) is on. Mirrors MoviePilot:
torrents are recognised only when matched to a subscription or searched,
and recognition failures are logged, not alerted.

- Pending items only for related releases (ambiguous after lookup, or
  related to a local work but unresolved); same source + normalized title
  merge into one decision ("来源「X」的 N 条资源待识别"), resolve/dismiss
  applies to the whole group, members detach as they get resolved.
- Pool governance: unmatched reviews capped (daily, 3x), title_alias
  insert trigger wakes similar entries, stale unmatched entries archived
  after identity.poolArchiveDays (30); review idempotency keys include the
  due time.
- Migration 0047_identity_pool: reason/outcome `unmatched`,
  identity_candidate.normalized_title (+trgm index), wake trigger, and
  cleanup of open identity_unresolved items with no related work
  (dismissed, resolution=moved_to_pool).
- Inbox: group by type + work/source with collapse, hide info-only items
  by default (minSeverity=warning), badge counts warning+ only; pool sheet
  gets manual TMDB/local-work assign and dismiss; settings card for the
  new identity settings.
- Runbook docs/runbook/identity.md.

Requires rebuild/restart (migration runs on start).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/web/app/components/library/identity-views.tsx

@@ -149,7 +149,7 @@ export function PoolTab() {
         empty={{
           icon: SearchX,
           title: filtered ? "没有符合条件的待识别资源" : "没有待识别资源",
-          description: "证据不足或冲突的资源会出现在这里，有新证据时自动重试。",
+          description: "未命中订阅、证据不足或冲突的资源会出现在这里；新增相近别名时自动重试，也可手动指定。",
         }}
         hasMore={pool.hasNextPage}
         onLoadMore={() => pool.fetchNextPage()}