feat: Data Management (DSGVO Art. 15/20/30 — export, inventory, retention)

- Data Management API: inventory (Art. 30 Verarbeitungsverzeichnis) + export
- JSON export with SHA-256 checksum (GoBD Jahresarchiv)
- CSV export (DATEV/Excel-compatible)
- Export history (audit-logged)
- Retention periods (8/6 years per GoBD)
- Art. 17 erasure notice (pseudonymization, legal precedence)
- 159 records across 10 categories with legal basis per category

src/components/aos/top-bar.tsx

@@ -33,6 +33,7 @@ const TITLES: Record<ViewId, { title: string; crumb: string }> = {
   finance: { title: 'Finanzen', crumb: 'Betrieb / Finanzen' },
   accounting: { title: 'Buchhaltung', crumb: 'Betrieb / Buchhaltung' },
   audit: { title: 'Audit-Protokoll', crumb: 'Betrieb / Audit' },
+  data: { title: 'Datenverwaltung', crumb: 'Betrieb / Daten' },
   kb: { title: 'Wissensdatenbank', crumb: 'Wissen / KB' },
   api: { title: 'API & Webhooks', crumb: 'System / API' },
   settings: { title: 'Erweiterungen', crumb: 'System / Module' },