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

tests/test_mma_approval_indicators.py

@@ -40,15 +40,16 @@ def _make_imgui_mock():
  m.begin_table.return_value = False
  m.begin_child.return_value = False
  m.checkbox.return_value = (False, False)
+ m.button.return_value = False
  m.input_text.side_effect = lambda label, value, *args, **kwargs: (False, value)
  m.input_text_multiline.side_effect = lambda label, value, *args, **kwargs: (False, value)
  m.combo.side_effect = lambda label, current_item, items, *args, **kwargs: (False, current_item)
  m.collapsing_header.return_value = False
+ m.begin_combo.return_value = False
  m.ImVec2.return_value = MagicMock()
  m.ImVec4.return_value = MagicMock()
  return m
 
-
 def _collect_text_colored_args(imgui_mock):
  """Return a single joined string of all text_colored second-arg strings."""
  parts = []