fix(ingest): address review round 1 (reclaim queue + tests)

- Register the periodic stalled-job reclaim on a dedicated ingest-maintenance
  queue that every worker drains (any --tier), so reclaim still fires when the
  fast fleet is scaled to zero and only ocr workers run. procrastinate's
  periodic-defer dedup keeps it single-run across drainers.
- escalation: mark `unsupported`/`forced` reason labels as reserved (not raised).
- processor: note that options/progress_callback are intentionally not threaded
  through _parse_pdf_tier yet (symmetric with the inline path).
- tests: assert TieredEscalationStrategy backoff progression (4/8/16/…/300s);
  cover get_ingest_pending per-queue aggregation + the legacy job_counts
  fallback; add an external-path zero-page no-escalation case; use the canonical
  INGEST_QUEUE_FAST instead of the back-compat alias.

Deck #323.

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

tests/unit/vector/test_procrastinate_producer.py

@@ -48,7 +48,8 @@ class TestProcrastinateTaskProducer:
         assert len(jobs) == 1
         job = jobs[0]
         assert job["task_name"] == pq.INGEST_TASK_NAME
-        assert job["queue_name"] == pq.INGEST_QUEUE_NAME
+        # New jobs are deferred onto the cheapest tier's queue.
+        assert job["queue_name"] == pq.INGEST_QUEUE_FAST
         assert job["queueing_lock"] == "alice:note:42"
         assert job["lock"] is None  # no execution lock (crash-deadlock guard)
         assert job["args"]["doc_id"] == "42"