node-002's root disk hit 100% (39.5 GB build cache + 16 GB unused images) and the node silently stopped recording for 17 days: BUILD=1 runs `docker compose build` on every update and nothing ever pruned the cache; the existing prunes only drop dangling images and old src- pins. After `up -d`: `builder prune -af --filter until=72h` and `image prune -af --filter until=168h`. Neither touches anything a running container uses; the age filters keep the next build's cache warm. Disk-free reporting to the portal (the other half of #41) is not in this change. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>