Switch backrest and filebrowser-colleen-hd to systemd automount bind mount

Replace Docker CIFS named volumes with bind mounts to /mnt/nas_backup,
which is managed by a systemd automount unit. This handles drive spin-down
reconnection independently of Docker container lifecycle.

filebrowser-colleen-hd/docker-compose.yml

@@ -6,7 +6,7 @@ services:
       FILEBROWSER_CONFIG: "data/config.yaml"
       TZ: "America/New_York"
     volumes:
-      - backup-mnt:/folder
+      - /mnt/nas_backup:/folder
       - /srv/filebrowser-colleen-hd:/home/filebrowser/data
     ports:
       - 3427:80
@@ -14,15 +14,7 @@ services:
       - npm-network
     restart: unless-stopped
 
-volumes:
-  backup-mnt:
-    driver: local
-    driver_opts:
-      type: cifs
-      o: "addr=192.168.1.192,username=${SMB_USERNAME},password=${SMB_PASSWORD},vers=3.0,uid=0,gid=0,file_mode=0755,dir_mode=0755,iocharset=utf8,noperm,noserverino,echo_interval=300"
-      device: "//192.168.1.192/backup"
-
 networks:
   default:
   npm-network:
-     external: true
+     external: true