feat: Credits-System mit Verbrauchsanzeige im User-Dropdown

- DB-Migration: credits_total/credits_used/cost_per_credit auf licenses, token_usage_monthly Tabelle
- Orchestrator: Monatliche Token-Aggregation + Credits-Abzug nach Refresh
- Auth: Credits-Daten im /me Endpoint + Bugfix fehlende Klammer in get()
- Frontend: Credits-Balken im User-Dropdown mit Farbwechsel

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

src/agents/orchestrator.py

@@ -1316,6 +1316,41 @@ class AgentOrchestrator:
                 f"${usage_acc.total_cost_usd:.4f} ({usage_acc.call_count} Calls)"
             )
 
+            # Credits-Tracking: Monatliche Aggregation + Credits abziehen
+            if tenant_id and usage_acc.total_cost_usd > 0:
+                year_month = datetime.now(TIMEZONE).strftime('%Y-%m')
+                await db.execute("""
+                    INSERT INTO token_usage_monthly
+                        (organization_id, year_month, input_tokens, output_tokens,
+                         cache_creation_tokens, cache_read_tokens, total_cost_usd, api_calls, refresh_count)
+                    VALUES (?, ?, ?, ?, ?, ?, ?, ?, 1)
+                    ON CONFLICT(organization_id, year_month) DO UPDATE SET
+                        input_tokens = input_tokens + excluded.input_tokens,
+                        output_tokens = output_tokens + excluded.output_tokens,
+                        cache_creation_tokens = cache_creation_tokens + excluded.cache_creation_tokens,
+                        cache_read_tokens = cache_read_tokens + excluded.cache_read_tokens,
+                        total_cost_usd = total_cost_usd + excluded.total_cost_usd,
+                        api_calls = api_calls + excluded.api_calls,
+                        refresh_count = refresh_count + 1,
+                        updated_at = CURRENT_TIMESTAMP
+                """, (tenant_id, year_month,
+                      usage_acc.input_tokens, usage_acc.output_tokens,
+                      usage_acc.cache_creation_tokens, usage_acc.cache_read_tokens,
+                      round(usage_acc.total_cost_usd, 7), usage_acc.call_count))
+
+                # Credits auf Lizenz abziehen
+                lic_cursor = await db.execute(
+                    "SELECT cost_per_credit FROM licenses WHERE organization_id = ? AND status = 'active' ORDER BY id DESC LIMIT 1",
+                    (tenant_id,))
+                lic = await lic_cursor.fetchone()
+                if lic and lic["cost_per_credit"] and lic["cost_per_credit"] > 0:
+                    credits_consumed = usage_acc.total_cost_usd / lic["cost_per_credit"]
+                    await db.execute(
+                        "UPDATE licenses SET credits_used = COALESCE(credits_used, 0) + ? WHERE organization_id = ? AND status = 'active'",
+                        (round(credits_consumed, 2), tenant_id))
+                await db.commit()
+                logger.info(f"Credits: {round(credits_consumed, 1) if lic and lic['cost_per_credit'] else 0} abgezogen für Tenant {tenant_id}")
+
             # Quellen-Discovery im Background starten
             if unique_results:
                 asyncio.create_task(_background_discover_sources(unique_results))