feat: reviewed-Status für Bilder, Auto-Trigger, Übersetzungen, Vertonbarkeits-Regel

- pictures: reviewed-Status (Constraint + ALLOWED_STATUSES + Auto-Trigger beim Object-Linking)
- objects: STATUSES um reviewed erweitert; Auto-Trigger draft→reviewed wenn Pair verlinkt
- pairs/statements/questions: STATUSES um reviewed (Phase-1-Lücke)
- pairs: POST /:id/review kaskadiert Pair+Frage+Statements (verlangt alle 3 Sprachen)
- words: Auto requested→translated wenn alle titel_* gefüllt (POST+PATCH)
- audios computeUnits: nur vertonbar wenn ALLE 3 Sprachen pro Feld gefüllt
- claude: translate-text/translate-row/translate-missing mit Placeholder-Schutz
  (⟦PHn:label⟧-Tokenisierung, Label übersetzt, UUID erhalten); translation-coverage

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/routes/questions.js

@@ -1,7 +1,7 @@
 const router = require('express').Router();
 const { query } = require('../db');
 
-const STATUSES = ['draft', 'blocked', 'published'];
+const STATUSES = ['draft', 'reviewed', 'blocked', 'published'];
 const STATUS_TIMESTAMP = { published: 'published_at', blocked: 'blocked_at' };
 
 // GET /api/questions