Align Windows sandbox temp permissions with the child environment

[copyberry]

Align Windows sandbox temp permissions with the child environment

Why

Windows temp grants could fall back to host TEMP/TMP values and bypass read-only or denied subpaths. Sandbox permissions must match the environment passed to the child process.

What changed

• Resolve :tmpdir from absolute TEMP/TMP paths in the completed workload environment, preserving access modes and missing-path rules without falling back to host values.
• Deduplicate Windows environment keys case-insensitively in a deterministic order so permission resolution and the child environment select the same value.
• Use the resolved temp policy for elevated sandbox overrides across core execution, exec-server, and direct spawning.
• Launch direct-spawn sandbox wrappers with the supplied Codex executable, materializing an inner helper only when it is that executable.

Testing

Add Windows regression coverage for temp-only writes, read-only and denied carveouts, mixed-case and duplicate environment keys, unavailable temp paths, and empty or missing write-root overrides. Exercise core execution and direct spawning, and extend exec-server RPC coverage to the elevated backend with temp values set through the environment policy.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	🔄 Running since 2026-10-06T23:21:19.266298Z	6763eda	PR opened

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