## Why
Unified exec can run commands on an OS that differs from the Codex host. Using
host path and shell semantics for approval checks can therefore miss dangerous
Windows and PowerShell commands sent to a remote executor.
## What changed
- Thread the executor platform through command parsing, executable-name
normalization, and dangerous-command classification. Legacy executors fall
back to the host platform, while unknown reported platforms use Windows rules
conservatively.
- Bound model-facing `exec_command` rejection messages and avoid echoing the
rejected command into the error.
- Keep deterministic process IDs reserved after release so rejected test
commands cannot reuse an earlier ID.
## Testing
- Add coverage that a long dangerous PowerShell command targeting a remote
Windows executor is rejected with a bounded response.
- Verify deterministic process IDs advance after release.
GitOrigin-RevId: a26b4a63ea3d6df7140032b88b3e7aec0b85b948
iceweasel-oai
1f4c47343a