Export serializes the current character via DataLoader.serialize() and
shows it in a scrollable monospace text dialog. Import accepts pasted
JSON, validates via DataLoader.deserialize(), and shows an error message
for invalid input. Both dialogs are accessible from the Settings page
and work on all platforms without platform-specific file I/O.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>