Fix Apple Watch chrome rendering from DeviceKit metadata

[DjDeveloperr]

Summary

• Rework chrome sizing for watch devices so the screen rect comes from DeviceKit metadata instead of a guessed rounded-rect approximation.
• Use the actual framebuffer mask to define the Watch screen cutout when a mask is present.
• Extend native chrome selection to include Apple Watch simulators and add focused coverage for the detector.

Testing

• npm run build:cli
• npm run --prefix client build
• npm test