enum WidgetProfiler

Per-widget paint cost, opt-in via LAVAUI_PROFILE=1.

Exists because tracking down a slow widget otherwise means manually wrapping suspects in FrameScheduler.now() calls, rebuilding, reading a log, and removing the probes again — which is exactly what it took to find that a 40,000-point chart, not the editor next to it, was the remaining cost after a large-file editor fix. This makes that the first thing you check, not the last.

Timed at widget granularity — one entry per leaf (a Canvas, an EditorView, a Button, …), not per draw primitive. Timing every rect/text/circle call individually would add far more overhead than the primitives themselves cost, swamping the very signal this exists to find; a widget's whole paint is the right unit; a Canvas doing something expensive internally still shows up as one number on one row.