fix(controller): Add stop_services() and dialog imports for GUI decoupling

- Add AppController.stop_services() to clean up AI client and event loop
- Add ConfirmDialog, MMAApprovalDialog, MMASpawnApprovalDialog imports to gui_2.py
- Fix test mocks for MMA dashboard and approval indicators
- Add retry logic to conftest.py for Windows file lock cleanup

src/gui_2.py

@@ -33,7 +33,7 @@ from log_pruner import LogPruner
 import conductor_tech_lead
 import multi_agent_conductor
 from models import Track, Ticket, DISC_ROLES, AGENT_TOOL_NAMES, CONFIG_PATH, load_config, parse_history_entries
-from app_controller import AppController
+from app_controller import AppController, ConfirmDialog, MMAApprovalDialog, MMASpawnApprovalDialog
 from file_cache import ASTParser
 
 from fastapi import FastAPI, Depends, HTTPException