feat: add notifications system with bell badge, polling, Directus flows, and webhook integration

README.md

@@ -155,7 +155,8 @@ dgray/
 │   │   ├── currency.js     # XMR/Fiat Umrechnung
 │   │   ├── pow-captcha.js  # PoW Captcha (Server-first, lokaler Fallback)
 │   │   ├── btcpay.js       # BTCPay Server Integration (Invoice, Checkout)
-│   │   └── favorites.js    # Favoriten (localStorage + Directus Sync)
+│   │   ├── favorites.js    # Favoriten (localStorage + Directus Sync)
+│   │   └── notifications.js# Benachrichtigungen (Polling, Badge)
 │   ├── vendor/
 │   │   ├── nacl-fast.min.js    # TweetNaCl (self-hosted)
 │   │   ├── nacl-util.min.js    # TweetNaCl Utils
@@ -217,7 +218,8 @@ dgray/
 - [x] Favoriten Directus-Sync (Union-Merge bei Login, localStorage-Fallback)
 - [x] PoW Captcha (server-seitig via pow.dgray.io, HMAC-signiert)
 - [x] TweetNaCl self-hosted (kein CDN)
-- [ ] Benachrichtigungen (Push)
+- [x] In-App Benachrichtigungen (Notifications-Service, Glocke mit Badge)
+- [ ] Push-Benachrichtigungen (Web Push API)
 
 ### Phase 4: Payments
 - [x] XMR-Kursabfrage API (CoinGecko)