chore(conductor): Mark track 'MMA Core Engine Implementation' as complete and verify with Phase 6 tests

gui_legacy.py

@@ -18,6 +18,7 @@ import sys
 import os
 from pathlib import Path
 from tkinter import filedialog, Tk
+from typing import Optional, Callable
 import aggregate
 import ai_client
 from ai_client import ProviderError