## Summary
- Remove the exec-server-side manual filesystem request path preflight
before invoking the sandbox helper.
- Keep sandbox helper policy construction and platform sandbox
enforcement as the access boundary.
- Add a portable local+remote regression for writing through an
explicitly configured alias root.
- Remove the metadata symlink-escape assertion that depended on the
deleted manual preflight; no replacement metadata-specific access probe
is added.
## Tests
- `cargo test -p codex-exec-server --lib`
- `cargo test -p codex-exec-server --test file_system`
- `git diff --check`
## Summary\n- add an exec-server package-local test helper binary that
can run exec-server and fs-helper flows\n- route exec-server filesystem
tests through that helper instead of cross-crate codex helper
binaries\n- stop relying on Bazel-only extra binary wiring for these
tests\n\n## Testing\n- not run (per repo guidance for codex changes)
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Co-authored-by: Codex <noreply@openai.com>