WAU Compliance: agent collector, backend endpoints, frontend badge + panel

- Agent: WAU registry config check (include/exclude URLs), pending updates count
- Backend: /wau/compliance per customer, /wau/compliance/summary all customers
- Frontend: compliance badge in customer list, compliance panel in WAU tab
- config.js: no longer gitignored (secrets-free, reads from env/window.__RMM_CONFIG__)
- vite.config.js: reads backend URL from .env instead of hardcoded value
- .env.example added for clean setup

.gitignore

@@ -34,8 +34,8 @@ updater/rmm-updater
 frontend/node_modules/
 frontend/dist/
 
-# config.js hat echte IPs und API-Keys — nie einchecken
-frontend/src/config.js
+# .env hat echte IPs und API-Keys — nie einchecken
+frontend/.env
 !frontend/src/config.example.js
 
 # ========================