chore(js): polish pong keys, held mapping and m09 main test

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

js/solutions/pong/app.js

@@ -8,14 +8,14 @@ import { keyDowns, keyUps, interval, map, filterMap, merge, scan, startWith } fr
 export const FRAME_MS_PONG = 30
 
 const keys = {
-  ArrowUp: 'Up', w: 'Up',
-  ArrowDown: 'Down', s: 'Down',
+  ArrowUp: 'Up', w: 'Up', W: 'Up',
+  ArrowDown: 'Down', s: 'Down', S: 'Down',
 }
 
 // hasOwn, not `key in keys`: "constructor" and "toString" are inherited, not keys we mapped.
 export const pongKey = (isDown, key) =>
   Object.hasOwn(keys, key) ? (isDown ? PongAction.Press : PongAction.Release)(keys[key])
-    : key === 'r' && isDown ? PongAction.Restart
+    : (key === 'r' || key === 'R') && isDown ? PongAction.Restart
     : null
 
 export const pongActions = merge(