Adds apps/editor/lib/bootstrap.ts that calls loadPlugin(builtinPlugin)
as a module-side-effect on first import. Imported from scene-loader.tsx
so it runs on the client side where the editor mounts.
Idempotency guard handles HMR re-execution (would otherwise throw on
duplicate registerNode). For the empty plugin this commit, the entire
call is a no-op — included now so future commits that add real node
kinds only need to push them onto builtinPlugin.nodes.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
