Add cron note

.cron

@@ -0,0 +1,17 @@
+Docker cleanup cron (host-side)
+
+Purpose:
+- Daily prune of unused images/containers/build cache for the runner host.
+- Keeps bind-mounted data safe (no named volumes removed).
+
+Schedule:
+- 04:00 daily
+
+Cron entry (root):
+0 4 * * * root /usr/bin/docker image prune -af --filter "until=24h" && /usr/bin/docker container prune -f && /usr/bin/docker builder prune -af --filter "until=24h"
+
+
+
+
+printf '%s\n' '0 4 * * * root /usr/bin/docker image prune -af --filter "until=24h" && /usr/bin/docker container prune -f && /usr/bin/docker builder prune -af --filter "until=24h"' | sudo tee /etc/cron.d/docker-prune
+cat /etc/cron.d/docker-prune