feat: durability and idempotency keys (#2450)

* feat: durability and idempotency keys

* feat: more durable frontend

* fix: tests

* fix: mini issues

* fix: better json validation

* fix: tests

tests/test_celery.py

@@ -19,3 +19,24 @@ def test_make_celery(mock_celery):
     )
     celery.conf.update.assert_called_once_with(settings)
     assert celery == mock_celery.return_value
+
+
+@pytest.mark.unit
+def test_celeryconfig_durability_defaults():
+    from application import celeryconfig
+
+    assert celeryconfig.task_acks_late is True
+    assert celeryconfig.task_reject_on_worker_lost is True
+    assert celeryconfig.worker_prefetch_multiplier == settings.CELERY_WORKER_PREFETCH_MULTIPLIER
+    assert celeryconfig.worker_prefetch_multiplier == 1
+    assert celeryconfig.broker_transport_options == {
+        "visibility_timeout": settings.CELERY_VISIBILITY_TIMEOUT
+    }
+    # 1h matches Onyx/Dify defaults; long enough for ingest, short enough
+    # that a SIGKILLed task redelivers within the same operator session.
+    assert celeryconfig.broker_transport_options["visibility_timeout"] == 3600
+    assert celeryconfig.result_expires == 86400 * 7
+    assert celeryconfig.task_track_started is True
+    # Project-scoped queue prevents a sibling worker on the same broker
+    # from grabbing DocsGPT tasks.
+    assert celeryconfig.task_default_queue == "docsgpt"