GitHub Actions macOS Runner No Space Left

When a macOS CI job fails with `No space left on device`, the fix should be a repeatable runner policy, not a random cleanup command pasted into every workflow.

Common high-risk sources

• Xcode DerivedData, ModuleCache.noindex, and build intermediates
• Unused simulator runtimes, unavailable devices, and DeviceSupport folders
• Homebrew, npm, pnpm, CocoaPods, SwiftPM, Gradle, and toolchain caches
• Large test artifacts, screenshots, videos, archives, and logs

Safer CI cleanup order

1. Print disk usage before cleanup so failures are diagnosable.
2. Remove workflow-local build output and dependency caches with the owning tool first.
3. Clean Xcode DerivedData and ModuleCache only after the job no longer needs those artifacts.
4. Review simulator runtime deletion separately; deleting the wrong runtime can break later jobs.
5. Print disk usage after cleanup and keep the numbers in the build log.

Starter commands

df -h
du -sh ~/Library/Developer/Xcode/DerivedData 2>/dev/null || true
du -sh ~/Library/Developer/CoreSimulator 2>/dev/null || true
du -sh ~/Library/Caches 2>/dev/null || true
xcrun simctl delete unavailable || true