Cancel the automatic startup General project as soon as a file is selected
or the lesson studio is requested, and re-check after the template fetch.
Prevents a slow remote first load from overwriting the user's scene.
Co-Authored-By: Claude Code <noreply@anthropic.com>
- Correct engine-manifest single wasm SHA and reuse cache for verification.
- Remove duplicate main-thread wasm fetch; raise init timeout to 300s.
- Record production deployment details and verification evidence.
Co-Authored-By: Claude Code <noreply@anthropic.com>