feat: add renovate stack (image update automation)

renovate/renovate.yaml

@@ -0,0 +1,22 @@
+services:
+  renovate:
+    image: renovate/renovate:latest
+    # Renovate runs as a one-shot job triggered by Woodpecker cron.
+    # This service definition exists for reference and manual runs only.
+    # Normal execution path: .woodpecker/renovate.yml cron pipeline.
+    environment:
+      RENOVATE_TOKEN: ${RENOVATE_TOKEN}
+      RENOVATE_PLATFORM: gitea
+      RENOVATE_ENDPOINT: https://${GITEA_HOST}
+      RENOVATE_GIT_AUTHOR: "Renovate Bot <renovate-bot@bryanmail.net>"
+      RENOVATE_REPOSITORIES: "homelab/compose-files"
+      LOG_LEVEL: info
+    deploy:
+      replicas: 0
+      placement:
+        constraints:
+          - node.hostname == docker-2
+      restart_policy:
+        condition: none
+
+networks: {}