[codex] Add PR quality gates

[ygsgdbd]

Summary

• add pinned SwiftFormat configuration and apply the initial formatting baseline
• add just recipes and a safe pre-commit hook for staged Swift files
• add pull request Format and Tests checks

Verification

• SwiftFormat lint: 0 files require formatting
• actionlint: passed
• pre-commit hook: verified no-change, fully staged, and partially staged behavior
• xcodebuild build-for-testing: passed
• local xcodebuild test: compiled successfully, but the macOS test host failed to launch twice with IDELaunchServicesLauncher / No such process; GitHub Actions will provide the authoritative test run

[chatgpt-codex-connector]

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