* fix(docker): pin base images to SHA256 digests for supply chain security
Pin all 9 Dockerfiles to immutable SHA256 digests to prevent supply chain
attacks where a compromised upstream image could be silently pulled into
production builds.
Also add Docker ecosystem to Dependabot configuration for automated
digest updates.
Images pinned:
- node:22-bookworm@sha256:cd7bcd2e7a1e6f72052feb023c7f6b722205d3fcab7bbcbd2d1bfdab10b1e935
- node:22-bookworm-slim@sha256:3cfe526ec8dd62013b8843e8e5d4877e297b886e5aace4a59fec25dc20736e45
- debian:bookworm-slim@sha256:98f4b71de414932439ac6ac690d7060df1f27161073c5036a7553723881bffbe
- ubuntu:24.04@sha256:cd1dba651b3080c3686ecf4e3c4220f026b521fb76978881737d24f200828b2b
Fixes#7731
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* test(docker): add digest pinning regression coverage
---------
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
