feat: Credits-System — Token-Usage-Router, Budget-Verwaltung, Frontend-Übersicht

- Neuer Router /api/token-usage mit Overview, Org-Detail, Monatsstatistik
- Budget-Felder (credits_total, cost_per_credit, token_budget_usd) bei Lizenz-Erstellung
- Token-Nutzung Sub-Tab in Org-Detail mit Verbrauchsbalken und Monatstabelle
- Dashboard Stat-Card für API-Kosten gesamt
- CSS Dark-Theme Styling für Token-Komponenten

src/routers/licenses.py

@@ -58,9 +58,11 @@ async def create_license(
         valid_until = (now + timedelta(days=365)).isoformat()
 
     cursor = await db.execute(
-        """INSERT INTO licenses (organization_id, license_type, max_users, valid_from, valid_until, status)
-           VALUES (?, ?, ?, ?, ?, 'active')""",
-        (data.organization_id, data.license_type, data.max_users, valid_from, valid_until),
+        """INSERT INTO licenses (organization_id, license_type, max_users, valid_from, valid_until, status,
+           token_budget_usd, credits_total, cost_per_credit, budget_warning_percent)
+           VALUES (?, ?, ?, ?, ?, 'active', ?, ?, ?, ?)""",
+        (data.organization_id, data.license_type, data.max_users, valid_from, valid_until,
+         data.token_budget_usd, data.credits_total, data.cost_per_credit, data.budget_warning_percent),
     )
     await db.commit()