test: add coverage for config TUI, ConfigField, schema changes, and CLI auto-setup
- test_config.py: GeneralConfig defaults, plugin_settings round-trip
- test_config_field.py: ConfigField dataclass, BasePlugin.config_fields() no-op,
plugin subclass override
- test_config_tui.py: _get/_set_nested, _fid/_pfid helpers, GENERAL_FIELDS validity,
ConfigApp general tab rendering, save handler, plugins table, plugin tab visibility,
q key exit — using Textual run_test() + Pilot
- test_cli.py: auto-setup wizard on first run, skip wizard when config exists,
/config in _STATIC_COMMANDS
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>