feat(sprint-6): Phase 2 — DSGVO consent management

- V6 migration: consents table with audit columns
- Consent entity, repository, service (grant/revoke/check)
- ConsentController: GET/POST/DELETE consent endpoints
- DSGVO export (Art. 15): full personal data JSON download
- DSGVO deletion (Art. 17): anonymization + account deactivation
- Frontend: consent banner (modal, cannot dismiss), privacy settings page
- React Query hooks for consent + DSGVO operations
- Full i18n (de/en) for consent and DSGVO namespaces

cannamanage-frontend/messages/en.json

@@ -343,5 +343,32 @@
     "notFound": "Resource not found.",
     "quotaExceeded": "Quota exceeded.",
     "serverError": "Server error. Please try again later."
+  },
+  "consent": {
+    "title": "Privacy Consent",
+    "dataProcessing": "Data Processing",
+    "dataProcessingDesc": "I consent to the processing of my personal data (name, email, date of birth, distribution history) for the purpose of club management. Legal basis: Art. 6(1)(a) GDPR.",
+    "marketing": "Marketing Notifications",
+    "marketingDesc": "I would like to receive information about new features and offers.",
+    "accept": "I agree",
+    "reject": "Decline and delete account",
+    "required": "Required",
+    "revoke": "Revoke consent",
+    "revokeWarning": "Without consent for data processing, the service cannot be used.",
+    "granted": "Granted on",
+    "revoked": "Revoked"
+  },
+  "dsgvo": {
+    "title": "Privacy",
+    "export": "Export my data",
+    "exportDesc": "Download all data stored about you as a JSON file (Art. 15 GDPR).",
+    "exportButton": "Download data",
+    "exporting": "Compiling data...",
+    "exported": "Data export downloaded.",
+    "delete": "Delete account and data",
+    "deleteDesc": "All personal data will be irreversibly deleted or anonymized (Art. 17 GDPR). Distribution data will be retained in anonymized form (legal retention requirement).",
+    "deleteButton": "Permanently delete account",
+    "deleteConfirm": "Are you sure? This action cannot be undone.",
+    "deleteSuccess": "Your account has been deleted. You will now be logged out."
   }
 }