Benchmark data: RealityKit versus a pixel-matched Metal renderer on Apple silicon

Raw measurements of a study comparing Apple's RealityKit with a Metal renderer calibrated to draw the same frames (the "twin"): headless frame-time sweeps and feature ablations on a MacBook Air (M5), CPU sampling profiles and GPU pass times, on-screen runs on an iPhone 12, an iPad Pro (A12X) and an iPhone 17 Pro Max, uncapped runs and battery-drain pairs on the iPhone 12, and powermetrics energy series on the M5. Includes the RealityKit and Metal-twin frames behind the frame-agreement figure, the Python scripts that turn the raw files into the study's tables and figures, the figures, and an Excel workbook per data chart. README.md maps every table and figure to its files. The renderer source code is available from the author upon reasonable request.