Codex preflight round 5: (1) an ended/timeout handler orphaned by stop()
could fire into a later stinger's lifecycle on the reused element — handlers
now detach unconditionally and carry a generation token; (2) the renderer
only re-applied cover-crop on camera aspect changes, so a src swap with a
different intrinsic size kept stale repeat/offset — it now recrops when
videoWidth/Height change.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>