feat: async significance pass with auto-pin on score 3

tests/test_memory_write.py

@@ -64,7 +64,7 @@ def test_record_turn_memory_writes_event_and_projects(tmp_path):
     apply_migrations(db)
     _seed_minimal(db)
     with open_db(db) as conn:
-        eid = record_turn_memory(
+        eid, mid = record_turn_memory(
             conn,
             chat_id="chat_bot_a",
             host_bot_id="bot_a",
@@ -73,6 +73,7 @@ def test_record_turn_memory_writes_event_and_projects(tmp_path):
             chat_clock_at="2026-04-26T20:00:00+00:00",
         )
         assert eid > 0
+        assert mid is not None and mid > 0
 
         rows = conn.execute(
             "SELECT id, owner_id, chat_id, pov_summary, "
@@ -110,13 +111,14 @@ def test_record_turn_memory_omits_optional_fields(tmp_path):
     _seed_minimal(db)
     with open_db(db) as conn:
         # Call without scene_id/chat_clock_at — should default to None.
-        eid = record_turn_memory(
+        eid, mid = record_turn_memory(
             conn,
             chat_id="chat_bot_a",
             host_bot_id="bot_a",
             narrative_text="A simple memory.",
         )
         assert eid > 0
+        assert mid is not None and mid > 0
 
         row = conn.execute(
             "SELECT scene_id, chat_clock_at, source, reliability, "
@@ -168,6 +170,11 @@ def client(tmp_path, monkeypatch):
     app.dependency_overrides[get_llm_client] = lambda: mock
 
     with TestClient(app) as c:
+        # Disable the lifespan-managed background worker — it would try
+        # to call Featherless with the test API key. The unit tests in
+        # test_significance.py exercise the worker directly with a mock
+        # factory; here we only care about the synchronous turn flow.
+        app.state.background_worker.enabled = False
         c.mock_llm = mock  # type: ignore[attr-defined]
         yield c