A test pins "Test" and "Bring level now" on Settings → Backups: a forge without a mirror says so, and only an admin may press them #7022

POST /settings/backups/test and /settings/backups/mirror/now (backupsTest and backupsMirrorNow in src/web/pages/backups.ts) have no test.

Done:

• [ ] Each case posts the form the way the page does, through readForm, with the session cookie and a same-origin Origin header. On a forge with no mirror, "now" answers "This forge has no mirror to bring level." as a danger flash.
• [ ] With a destination the test cannot reach, "Test" says it failed in words, and no stack trace or credential reaches the page.
• [ ] A non-admin and a cross-origin post are refused for both.

Files: test/settings-backups-buttons.test.ts

If the test finds the behaviour wrong, fix the handler it names in the same pull and say so. If the check fails in a test this pull does not touch, name it in the pull rather than widening the change.

Before pushing: bun x tsc --noEmit and the new test.