feat: add diun stack, migrate notifications from gotify to ntfy

ops/diun/docker-compose.yml

@@ -0,0 +1,31 @@
+services:
+  diun:
+    image: crazymax/diun:4.31.0
+    container_name: diun
+    hostname: diun
+    command: serve
+    restart: unless-stopped
+    environment:
+      TZ: Europe/Berlin
+      LOG_LEVEL: info
+      LOG_JSON: "false"
+      DIUN_WATCH_WORKERS: "20"
+      DIUN_WATCH_SCHEDULE: "0 */6 * * *"
+      DIUN_WATCH_JITTER: "30s"
+      DIUN_PROVIDERS_DOCKER: "true"
+      DIUN_PROVIDERS_DOCKER_WATCHBYDEFAULT: "false"
+      DIUN_PROVIDERS_DOCKER_WATCHSTOPPED: "false"
+      # Notifications via ntfy (replaced gotify)
+      DIUN_NOTIF_NTFY_ENDPOINT: https://ntfy.kaleschke.info
+      DIUN_NOTIF_NTFY_TOPIC: diun
+    volumes:
+      - /mnt/user/appdata/diun:/data
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+    security_opt:
+      - no-new-privileges:true
+    networks:
+      - frontend_net
+
+networks:
+  frontend_net:
+    external: true