UI Performance Benchmark (Real Compiled Yichus)

This benchmark compiles Yichus `.bosatsu` source via the `sim --emit js` pipeline and measures the generated runtime directly. React 18 uses `createRoot` + `useState` with production builds.

Numbers vary by browser and machine. Run multiple times.

Yichus batch size Yichus flush delay

Scenario	Yichus avg (ms)	Yichus ops/sec	React avg (ms)	React ops/sec	Speedup vs React
Click a benchmark button.