fix(test): disable switch explicitly now that auto-apply defaults ON

test_auto_apply_disabled_blocks_real_run assumed head_auto_apply_enabled
defaulted False; it now defaults True (opt-out), so a real sweep is accepted
(202). Set the switch off in the test to exercise the disabled→400 path.
(run 1629)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ttrj5P7upUTueSfoJcxEqa

tests/test_head_auto_apply.py

@@ -117,7 +117,11 @@ def test_sweep_skips_ungraduated_head(db_sync):
 
 @pytest.mark.asyncio
 async def test_auto_apply_disabled_blocks_real_run(client, db):
-    # head_auto_apply_enabled defaults False → a real sweep is refused (400).
+    # With the master switch OFF, a real sweep is refused (400). (It defaults ON
+    # now — opt-out — so the test disables it explicitly to exercise this path.)
+    s = (await db.execute(select(MLSettings).where(MLSettings.id == 1))).scalar_one()
+    s.head_auto_apply_enabled = False
+    await db.commit()
     resp = await client.post("/api/heads/auto-apply", json={"dry_run": False})
     assert resp.status_code == 400
     assert (await resp.get_json())["error"] == "auto_apply_disabled"