Summary

• Wake Apple SPU HID drivers before opening the accelerometer stream.
• Add a privileged local sensor helper for macOS builds that require elevated access to live SPU reports.
• Stream sensor samples as JSON lines and cover the roundtrip in tests.

Verification

• swift test
• xcodebuild -project SlamX.xcodeproj -scheme SlamX -configuration Release -destination 'platform=macOS' build
• Release helper smoke test against .build/xcode-release/Release/SlamX.app streamed live accelerometer JSON samples.