fix: detect Codex in nested ChatGPT macOS app bundle

[wsgxy986]

Summary

Fix Codex runtime discovery for newer ChatGPT macOS app bundles. First Tree 0.5.23 failed to start a Codex chat even though the executable was installed and runnable at:

/Applications/ChatGPT.app/Contents/Resources/codex-cli/CodexCLI.app/Contents/MacOS/codex

• Add the nested app bundle directory for both /Applications and ~/Applications.
• Preserve existing PATH precedence and legacy app locations.
• Add regression tests for system-wide and per-user installations.

Creating a ~/.local/bin/codex symlink and restarting the daemon restored discovery on the affected machine. This change makes that workaround unnecessary for this installation layout.

Validation

• Both new regression cases failed before the fix and passed afterward.
• All 35 tests in source-repos.test.ts and providers/codex/__tests__/binary.test.ts passed.
• Client TypeScript check passed.
• Repository-wide Biome check passed with existing warnings.
• git diff --check passed.
• Full repository typecheck and tests were attempted but blocked by the local dependency setup (ERR_PNPM_IGNORED_BUILDS). They are not claimed to have passed.

Notes

• No package version changes or public CLI changes.
• Related QA case: packages/qa/cases/runtime/daemon-probe-capability.md.
• Draft pending full CI validation and contributor identity/CLA checks.

[github-actions]

All contributors are covered by the First Tree CLA.
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[wsgxy986]

@yuezengwu Could you please take a look at this macOS Codex runtime discovery fix? It adds support for the nested Codex binary in newer ChatGPT app bundles. This is currently a draft: the focused regression tests and client typecheck pass, while full CI validation and contributor identity/CLA checks remain pending.

[wsgxy986]

I have read the CLA Document and I hereby sign the CLA

[yuezengwu]

The new nested ChatGPT app-bundle candidates cover both system and per-user installations while preserving existing PATH precedence and legacy app fallbacks. No blocking findings in the three changed files at b52a18b (base 13f2a38).

Validation: CI run 36705741566, attempt 2, succeeded with 12 successful jobs and one skipped job. The latest CLA run also succeeded. The regression tests cover discovery in both installation locations.