add /account dashboard

- xBZZ balance prominently
- API keys: create / list / revoke; new key surfaced once in a copy dialog
- Recent ledger entries (welcome credit, job charges, top-ups)
- Auth: JWT from localStorage; 401 clears JWT + redirects to /login
- Sign-out button

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

app/routes.ts

@@ -5,4 +5,5 @@ export default [
   route('signup', 'routes/signup.tsx'),
   route('verify', 'routes/verify.tsx'),
   route('login', 'routes/login.tsx'),
+  route('account', 'routes/account.tsx'),
 ] satisfies RouteConfig;