feat(chat): retry the last answer — redo-in-place Retry button on the latest brain bubble

tests/unit/test_sources_midstream.py

@@ -99,11 +99,12 @@ def test_persisted_on_leave_flag_is_module_scoped_and_turn_reset() -> None:
         "flag check first, set immediately before the persist call"
     )
 
-    # Reset at the top of the turn handler (handleSend) — before the
-    # turn's fetch, where the other turn locals are initialized.
-    send = js.find("async function handleSend")
-    assert send != -1
-    top = js[send : send + 1500]
+    # Reset at the top of the turn handler (runTurn — phase 49 extracted
+    # the turn from handleSend) — before the turn's fetch, where the
+    # other turn locals are initialized.
+    turn = js.find("async function runTurn")
+    assert turn != -1
+    top = js[turn : turn + 1500]
     assert "persistedOnLeave = false;" in top, (
         "persistedOnLeave must be reset per turn, at the top of the turn handler"
     )