test_image_monitor_singleton replaced utils.comfyui_integration in
sys.modules with a MagicMock and never restored it, so running it before
test_comfyui_integration failed eight tests. The mock was unused; drop it
and install the server stub with setdefault in every owned test module.
The PromptSearchList IS_CHANGED test slept 10 ms between two time.time()
reads; the Windows clock ticks every 15.6 ms, so it was flaky there. Mock
the clock with an incrementing counter instead.