Track CVE fixes from 2026-04-20 audit
Tracking issue for CVE fixes landed via !1138.
## Related MR
- Merge request: https://gitlab.com/postgres-ai/database-lab/-/merge_requests/1138
## Scope
CVE sweep from the 2026-04-20 audit:
- docker/cli → v29.4.0 (CVE-2025-15558)
- otel/sdk, otel API, otlptrace, otlptracehttp → v1.43.0 (CVE-2026-24051, CVE-2026-39883)
- grpc → v1.80.0 (supersedes CVE-2026-33186 fix in v1.79.3)
- Base image bumped to `docker:29.4.0` pinned by digest `@sha256:a6dd5322747a95cd8e3207bd8d415a8fd20ec34e9c00f06dc019cbd912013489`
- `apk upgrade` for musl, openssl, zlib (CVE-2026-28390, CVE-2026-40200, CVE-2026-22184)
- `Dockerfile.ci-checker` aligned to `docker:29.4.0`
## Known unfixed (tracked in SECURITY.md)
- `github.com/docker/docker v28.5.2+incompatible` — CVE-2026-34040 (no v29 tag; upstream moved to `github.com/moby/moby/v2`, still in beta)
- CVEs in embedded base-image binaries (containerd, ctr, dockerd, compose, buildx) — pending Docker Inc rebuild of `docker:29.x`
- `Dockerfile.dblab-server-zfs08` stays on `docker:27.5.1` for ZFS 0.8 compatibility on Alpine v3.12
issue