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

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>

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(

js/solutions/pong/rules.js

@@ -56,10 +56,16 @@ const frame = (state) => {
   return scorer === null ? next : serve(next, scorer)
 }
 
+// Only the keys the model knows ('Up', 'Down') are held; anything else leaves the state alone.
+const heldFlag = { Up: 'up', Down: 'down' }
+
+const setHeld = (state, key, value) =>
+  Object.hasOwn(heldFlag, key) ? { ...state, held: { ...state.held, [heldFlag[key]]: value } } : state
+
 export const pongUpdate = (state, action) => {
   switch (action.tag) {
-    case 'Press': return { ...state, held: { ...state.held, [action.key.toLowerCase()]: true } }
-    case 'Release': return { ...state, held: { ...state.held, [action.key.toLowerCase()]: false } }
+    case 'Press': return setHeld(state, action.key, true)
+    case 'Release': return setHeld(state, action.key, false)
     case 'Restart': return initialPong(state.seed)
     case 'Frame': return frame(state)
     default: return state