feat(js): m11 pong capstone (model, rules, view, app, page) and polling smoke test

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

js/solutions/pong/main.js

@@ -0,0 +1,5 @@
+import { runApp } from '../runtime.js'
+import { browserPlatform } from '../browser.js'
+import { pongMain } from './app.js'
+
+runApp(pongMain, browserPlatform(document.getElementById('game'), window))