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/store/aos.ts

@@ -18,6 +18,7 @@ export type ViewId =
   | 'finance'
   | 'accounting'
   | 'audit'
+  | 'data'
   | 'api'
   | 'kb'
   | 'calendar'