Add macOS x64 desktop and CLI releases

[linroid]

Intel Macs currently have no desktop or CLI release artifacts, and the installer rejects macOS x64. Add Intel runner jobs for the desktop DMG and native CLI archive, allow the installer to download the x64 archive, and update the supported-platform documentation.

Fix the installer's EXIT cleanup trap to capture its temporary path before local variables leave scope; otherwise a successful installation exits with an unbound-variable error.

Validation:

• Release YAML and matrix checks passed, including unique artifact names and Intel runner selection.
• Bash syntax and git diff checks passed.
• Mocked x64 and arm64 installs passed URL selection, extraction, executable launch, and temporary-directory cleanup (including paths with spaces and quotes).
• Full Intel desktop and GraalVM builds have not been run locally; the release jobs will build them on macos-15-intel.

[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	✅ Completed 2026-09-27T07:44:24.667691Z	a2ebf70	PR opened

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[github-actions]

Test Results

  871 files  ±0    871 suites  ±0   6m 1s ⏱️ +2s
3 873 tests ±0  3 873 ✅ ±0  0 💤 ±0  0 ❌ ±0 
5 203 runs  ±0  5 203 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit a2ebf70. ± Comparison against base commit 8ba0963.