Errors on sign-in, passkeys, the first-admin form and the claim page are §5's field error, not .error-note #5068

Intent: same pattern as #4807.

Done:

• [ ] src/web/pages/passkeys.ts (2), everyday.ts (data-fail="error-note", which src/web/client.ts reads), first-admin.ts and claim.ts no longer write error-note. A failure the client shows uses the same .error shape
• [ ] one test for each page's error path finds the error in its field or at the form's head
• [ ] the .error-note rule and §5d stay; another issue removes them