## Why
A repository can contain a tracked directory that Git implicitly treats as a bare
repository. Its configuration may select helpers such as `core.fsmonitor`, causing
Codex Git operations in that directory to execute repository-controlled code.
## What changed
- Pass `-c safe.bareRepository=explicit` to Codex-managed Git commands so they
reject implicitly discovered bare repositories.
- Continue to support repositories explicitly selected with `--git-dir` or
`GIT_DIR`.
## Testing
Add a regression test that clones a repository containing a tracked embedded Git
repository and verifies that guarded Git inspection rejects it without running
its configured filesystem monitor.
GitOrigin-RevId: 344b5bc1e0ffa94f2a1b788488aa653222da10f3