Debug panel

DebugPlugin (in CorePlugins) is a Tweakpane inspector for dev builds. It does nothing headless, in production builds, or in kiln shot.

Section
Stats	FPS (with a 12-second graph), frame time, frame, tick, entity count, renderer backend
Control	Pause, step one frame, snapshot to the console, vsync and an FPS cap
Systems (ms)	Per-system timings, smoothed
Entity	Pick an entity by id and edit its trait fields live
Resources	Every resource as JSON

Toggle it with the ` key; ?debug=0 in the URL hides it.

debugPlugin({ open: false }) starts it collapsed, and force: true shows it outside dev builds.

Turning the plugin on sets app.profile, which records per-system timings. Headless runs leave it off.