The canonical .dockerignore kept out .git/config and the configs under
.git/modules/, but not the config of a submodule that keeps its own .git
directory, so its credential reached the image. Both git patterns now
carry the **/ prefix.
A submodule whose name has a config segment (config, deploy/config,
config/lib) still loses its whole git directory, and Go's version
stamping fails the build. Closing that needs a wildcard re-include,
which makes BuildKit walk every excluded directory on every build, so
the file records it as a KNOWN GAP with the remedy, git submodule add
--name. REPO_POLICIES.md and both checklists say the same.
Model: opus-5-5
sneak