fix: initialize document processors in the ingest worker (PR #836 round-5)

🟡 The `worker` command never called initialize_document_processors(), so a
worker pod with ENABLE_UNSTRUCTURED/TESSERACT/CUSTOM configured silently ran
PyMuPDF-only (only the import-time-registered processor). The always-on API pod
registers them in its lifespan; the worker has its own startup path, so call
initialize_document_processors() there too (before run_worker_async).

🟢 Drop the unused get_database_url monkeypatch in the Postgres integration
fixture (build_app_for_url passes the URL explicitly; only the ssl lookup needs
pinning).

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

tests/integration/test_ingest_queue_postgres.py

@@ -78,8 +78,8 @@ async def fresh_app(postgres_url: str, monkeypatch: pytest.MonkeyPatch):
     finally:
         await engine.dispose()
 
-    # get_procrastinate_conninfo derives ssl from settings; point it at the URL.
-    monkeypatch.setattr(config_module, "get_database_url", lambda: postgres_url)
+    # build_app_for_url passes the URL explicitly to get_procrastinate_conninfo,
+    # so only the ssl lookup (which reads settings) needs pinning here.
     monkeypatch.setattr(config_module, "get_database_ssl", lambda: None)
 
     app = build_app_for_url(postgres_url)