- Extract _load_data() method from load_path() for reuse in reload()
- Add is_extters externally_modified() to track file state changes (mtime/size)
- Replace load_bytes() with load_contents() for better error handling
- Add reload() method to re-read file from disk
- Fix file_state_watcher by properly detecting external changes
- Update TODO list (add Terminal plugin, mark file_state_watcher as fixed)