chore(tests): Final stabilization of test suite and full isolation of live_gui artifacts

tests/test_gui_phase3.py

@@ -4,13 +4,6 @@ from pathlib import Path
 from unittest.mock import MagicMock, patch
 import pytest
 
-# Mocking modules that might fail in test env
-import sys
-sys.modules['imgui_bundle'] = MagicMock()
-sys.modules['imgui_bundle.imgui'] = MagicMock()
-sys.modules['imgui_bundle.immapp'] = MagicMock()
-sys.modules['imgui_bundle.hello_imgui'] = MagicMock()
-
 from gui_2 import App
 
 def test_track_proposal_editing(app_instance):