Adds test.js — a zero-dependency Node.js test harness that validates:
- JS syntax (node --check) for app.js and ws-client.js
- File size budget (< 500 KB per JS file)
- JSON validity for manifest.json, portals.json, vision.json
- HTML structure of index.html (DOCTYPE, importmap, required elements)
- Static analysis of app.js for required scene components
(scene, camera, renderer, animate loop, star field, ws-client, etc.)
Run with: node test.js
Fixes#145
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
