feat(intake): settings for the submission ceiling (#227)

A count type beside the existing hours, text and choice readers. resolveHours would have worked — it is parseFloat with a positive guard — but calling a submission ceiling an "hours" setting is a lie in the type name that every later reader has to decode. Whole numbers only, so a ceiling of 12.5 is a typo rather than a preference, and a malformed value falls back rather than yielding a NaN that compares false against everything and silently disables the limit.

resetDb is widened to clear intake_ settings as well as email_ ones. It deliberately does not truncate admin_settings, so a ceiling of 1 left behind by one suite would make every later suite's submissions refuse with a 503, in files that never mention a ceiling. The comment there already records that exact failure happening once with an email template subject, which reached the favorite-alert tests and failed five of them somewhere else entirely.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

backend/tests/integration/adminSettings.integration.test.ts

@@ -33,7 +33,10 @@ describe('GET /api/admin/settings', () => {
       draftingModel: 'claude-sonnet-5',
       // Empty by default: nowhere to send the intake notification is a working
       // configuration, and means simply do not send one (#224).
-      intakeNotifyEmail: ''
+      intakeNotifyEmail: '',
+      intakeDailyCeiling: 100,
+      intakeLinkAlertThreshold: 20,
+      intakeCeilingResetAt: ''
     });
   });
 });