Sprint 18: Notification Center, Routen entdecken, Onboarding, Admin-Erweiterungen

- Notifications: History-Tabelle, /api/notifications Endpoints, push.py schreibt in DB
- Notifications: Page (notifications.js) mit Badge, Typen-Icons, gelesen-Markierung
- Routen: Entdecken-Modus mit Ersteller-Anzeige, Nearby-Filter, Mine/Discover Toggle
- Onboarding: Willkommens-Modal nach Registrierung, Push-Angebot nach Login
- Admin: Scheduler-Tab (Jobs anzeigen + manuell triggern), System-Health (DB/Disk/Uptime)
- Admin: Audit-Log (wer hat was wann gemacht), erweiterte Stats (Push-Abos, aktive User, Routen)
- SW: by-v152, APP_VER 125

backend/static/js/api.js

@@ -433,6 +433,17 @@ const API = (() => {
     snapshot: () => get('/widget/snapshot'),
   };
 
+  // ----------------------------------------------------------
+  // NOTIFICATIONS
+  // ----------------------------------------------------------
+  const notifications = {
+    list()        { return get('/notifications'); },
+    unreadCount() { return get('/notifications/unread-count'); },
+    readAll()     { return patch('/notifications/read-all', {}); },
+    read(id)      { return patch(`/notifications/${id}/read`, {}); },
+    delete(id)    { return del(`/notifications/${id}`); },
+  };
+
   const importData = {
     notestation(dogId, file) {
       const fd = new FormData();
@@ -465,7 +476,7 @@ const API = (() => {
     get, post, put, patch, del, upload,
     auth, dogs, diary, health, tieraerzte, poison,
     places, routes, walks, events, sitting, forum, lost, knigge, weather, push,
-    friends, chat, webcal, importData, sharing, widget,
+    friends, chat, webcal, importData, sharing, widget, notifications,
     subscribeToPush, getLocation,
     APIError,
   };