Profiles and speeds up a heavy three.js WebGL scene with multi-pass rendering (refraction/reflection pre-passes, GTAO, bloom, shadows, thousands of instances) — honest GPU timing with gl.finish and a default-framebuffer readPixels, per-pass on/off toggles, triangles-per-mesh reports, shader-compile hitch warm-up, one shared shadow render per frame, render layers, distance culling and LOD, no-recompile light fading, program-cache keys, adaptive resolution and GLB compression.
