Audit upstream Codex macOS desktop behavior

[andrei-hasna]

Summary

• Add macOS audit artifact comparing current upstream Codex desktop behavior with the CodeWith macOS app.
• Document that refreshed upstream/main f6e251c3ac has no macos Swift app tree, so the concrete upstream inheritance target is the CLI desktop open/install behavior.
• Capture preserve constraints for CodeWith branding, codewith:// deep links, auth profiles, Machines, Loops, Goals, Workflows, Apps, and no upstream update prompts.
• Created follow-up todo af56a114 for the narrow missing default installer URL selection implementation.

Validation

• git diff --check
• git diff --cached --check
• gitleaks protect --staged --config .gitleaks.toml

Notes

• Doc-only change; no Rust or Swift tests were run.
• Local git hook environment printed Can't find lefthook in PATH, but commit and push completed.

[andrei-hasna]

Closing as superseded by #207. Replacement #207 carries the current provider/docs cleanup slice and explicitly lists this PR in its carried scope. Please continue review on #207.