The sidecar's `docker compose up` command lacked `--pull never`, so Docker Compose would attempt to pull the caddy image from ghcr.io when the local image was missing or stale. Since the sidecar has no registry credentials this failed with 403 Forbidden. Closes #117 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>