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>
.badge lacked text-align: center. Inside the card's flex-end right
column, badge text was left-justified within each pill, making state
labels (deployed / testing / degraded) appear skewed to the left.
TDD: CSS regression test added to tests/helpers.test.js — reads
css/app.css directly and asserts the rule is present, so this
cannot regress silently in future.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
