feat: Stadium Elite Design, Rangliste, Profil-Team, User-Upsert & n8n Cronjob

- MatchCard + TipModal: Uhrzeit statt VS zwischen Flaggen, Gruppe zentriert
- LeaderboardPage: Podium (2./1./3.), DU-Badge, Trend-Pfeile, Team-Zeile, CTA-Card
- AdminPage: Stadium Elite Redesign mit Result-Bar und Inline-Spinner
- ProfilePage: Team-Feld inline editierbar (PATCH /api/profile/team)
- User-Upsert beim ersten App-Aufruf (Matches-Route) statt erst beim Tipp
- DB Migration 002: team-Spalte in users, Leaderboard View aktualisiert
- Leaderboard-Refresh automatisch nach Tipps-Auswertung
- n8n Workflow angelegt: stündlicher Sync + Auswertung (ID: t3SDspIGDXwkfOt3)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/src/index.ts

@@ -13,6 +13,7 @@ import matchesRouter from './routes/matches';
 import tipsRouter from './routes/tips';
 import leaderboardRouter from './routes/leaderboard';
 import adminRouter from './routes/admin';
+import profileRouter from './routes/profile';
 
 const app = express();
 const PORT = parseInt(process.env.PORT ?? '3001');
@@ -116,6 +117,7 @@ app.use('/api/matches', matchesRouter);
 app.use('/api/tips', tipsRouter);
 app.use('/api/leaderboard', leaderboardRouter);
 app.use('/api/admin', adminRouter);
+app.use('/api/profile', profileRouter);
 
 // ============================================================
 // Frontend (React Build) – statisches Serving