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>

packages/db/src/schema/journal.ts

@@ -29,6 +29,7 @@ export const users = journalSchema.table("users", {
   displayName: text("display_name"),
   bio: text("bio"),
   domain: text("domain").notNull(),
+  termsAcceptedAt: timestamp("terms_accepted_at", { withTimezone: true }),
   createdAt: timestamp("created_at", { withTimezone: true }).notNull().defaultNow(),
 });