Explain full Core Animation commit pipeline per frame

UIView updates → CALayer tree → CATransaction → Render Server → GPU composition → display vsync.

UIKit modifies CALayer properties. At runloop boundary, CATransaction commits changes. These are serialized and sent to render server (backboardd/renderd). Render server computes render tree, rasterizes layers if needed, and sends GPU commands via Metal. Display refresh occurs at vsync (60/120Hz).