- Replace DEFAULT_SETTINGS.copy() with copy.deepcopy(DEFAULT_SETTINGS) in
load_settings() and save_settings() to prevent mutation of module-level
mutable defaults (hidden_sessions list was shared via shallow copy)
- Replace except (json.JSONDecodeError, Exception) with
except (FileNotFoundError, json.JSONDecodeError) to only suppress expected
errors and let unexpected exceptions (PermissionError etc.) propagate
- Add two regression tests:
test_load_does_not_mutate_default_settings: verifies deepcopy isolation
test_load_propagates_non_json_errors: verifies narrow exception handling
Brian Krabach