Add legal pages, ToS acceptance, and alpha banner

- Journal: Impressum (§5 TMG), Terms of Service, GDPR privacy page
- Registration flow: required ToS checkbox, termsAcceptedAt persisted
- Alpha banner on Journal (always visible); alpha badge on Planner hero
- Footer with legal links + GitHub on both apps
- Reduce PII: sendDefaultPii=false, Sentry init only after login (Journal)
- Drop Sentry from Planner (no login, no consent possible)
- Drop localStorage caching from i18n client detection
- Sync SSR i18n resources each request so locale edits HMR without restart

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/mobile/lib/sentry.ts

@@ -7,6 +7,7 @@ export function initSentry() {
     dsn: SENTRY_DSN,
     tracesSampleRate: __DEV__ ? 0 : 1.0,
     enabled: !__DEV__,
+    sendDefaultPii: false,
   });
 }