fix(backup): use message field in webhook payload, matching watchtower

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -68,6 +68,16 @@ ssh vps 'systemctl status stacks-backup.timer'
 ssh vps 'source ~/stacks/_backup/.env && restic -r /mnt/hidrive/users/valknar/Backup/stacks snapshots'
 ```
 
+## Notifications
+
+Watchtower and the backup script both POST to an n8n webhook, which forwards messages to Telegram.
+
+The webhook URL is set in two places:
+- `_backup/.env` → `WEBHOOK_URL`
+- `watchtower/.env` → `NOTIFICATION_URL` (uses `generic+https://` shoutrrr scheme)
+
+Both point to the same n8n workflow at `https://n8n.pivoine.art`. The workflow accepts `{ "message": "..." }` from both senders and forwards it to Telegram.
+
 ## Data
 
 Persistent data is stored in `~/stacks/.data/<stack>/` on the VPS using bind mounts. Database stacks use dedicated Postgres instances with simple credentials.

_backup/backup.sh

@@ -20,7 +20,7 @@ notify() {
   local color="$1" text="$2"
   curl -sf -o /dev/null -X POST "$WEBHOOK_URL" \
     -H 'Content-Type: application/json' \
-    -d "{\"text\":\"$text\",\"color\":\"$color\"}"
+    -d "{\"message\":\"$text\",\"color\":\"$color\"}"
 }
 
 # Truncate log on each run