- Change split pane close shortcut from Ctrl+Shift+W to Alt+\
- Register new TextInsertEvent in event system exports
- Prepare groundwork for handling low-level text insertion events in editor pipeline
- Delete deprecated split_pane_manager command plugin and all related commands
- Introduce new split_pane command structure (untracked replacement)
- Add guard in code_minimap to handle missing active view
- Prevent language detection for non-file buffers in command_helpers
This cleans up legacy split pane logic and improves stability for edge cases.
