fix(crawler): harden crash & shutdown job recovery

Three failure-mode fixes surfaced by a crawler recovery audit:

- Graceful shutdown mid-dispatch now releases the in-flight job back to
  pending without burning a retry attempt. process_lease wraps the
  dispatch in a biased tokio::select! cancel arm that aborts the
  heartbeat and calls jobs::release; previously a mid-job SIGTERM left
  the row 'running' until lease expiry and cost one of max_attempts.

- Boot-time jobs::reclaim_orphaned resets 'running' jobs with an expired
  lease back to pending (attempt refunded), run once at daemon startup
  before workers start. Crash recovery is now immediate instead of
  waiting a full lease window for the lazy lease-expiry path. Safe under
  multi-replica: only already-expired leases are touched, which a
  healthy heartbeating peer never has.

- Manga-list parsing now warns when listing anchors are dropped for a
  missing/empty href or title (split into parse_manga_list_anchors so
  the drop count is testable), turning silent source markup drift into
  an observable signal. Returned refs are byte-identical to before.

Tests added: shutdown_mid_dispatch_releases_lease_without_burning_attempt,
reclaim_orphaned_resets_only_expired_running_jobs, and a drop-count unit
test. Patch bump 0.81.0 -> 0.81.1 (both manifests).

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

frontend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mangalord-frontend",
-  "version": "0.81.0",
+  "version": "0.81.1",
   "private": true,
   "type": "module",
   "scripts": {