Stacks are always just production/development — counting them adds
no useful information to the dashboard summary.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Adds a gear button to the nav that opens a settings modal with:
- Export: GET /api/export returns all instances as a JSON backup file
with a Content-Disposition attachment header
- Import: POST /api/import validates and bulk-replaces all instances;
client uses FileReader to POST the parsed JSON, with a confirm dialog
before destructive replace
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
