fix(tests): resolve 3 test failures in GUI decoupling track

- conftest.py: Create workspace dir before writing files (FileNotFoundError)
- test_live_gui_integration.py: Call handler directly since start_services mocked
- test_gui2_performance.py: Fix key mismatch (gui_2.py -> sloppy.py path lookup)

tests/conftest.py

@@ -187,6 +187,8 @@ def live_gui() -> Generator[tuple[subprocess.Popen, str], None, None]:
     break
    except PermissionError:
     time.sleep(0.5)
+ # Create the workspace directory before writing files
+ temp_workspace.mkdir(parents=True, exist_ok=True)
  
  # Create minimal project files to avoid cluttering root
  # NOTE: Do NOT create config.toml here - we use SLOP_CONFIG env var