Inside the app container localhost resolves to ::1 (IPv6) first, but the
Next.js standalone server listens only on 0.0.0.0 (IPv4). The healthcheck
probed http://localhost:3000/api/health and got Connection refused on ::1,
so the container reported unhealthy for weeks despite serving 200 on both
/ and /api/health. Switch the probe to 127.0.0.1 to match the bound iface.
The db and embedder healthchecks already avoid localhost.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>