- Added _render_external_editor_panel method to display configured editors
- Shows default editor marker and diff args
- Displays config file locations for user reference
- Integrated as 'External Editor' section in AI Settings
- Add TextEditorConfig and ExternalEditorConfig dataclasses to models.py
- Create src/external_editor.py with ExternalEditorLauncher class
- Add tests for configuration and launcher functionality
- Support for config.toml [tools.text_editors] and manual_slop.toml default_editor