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

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

fixtures/m11-pong-key.json

@@ -146,6 +146,68 @@
         "toString"
       ],
       "expected": null
+    },
+    {
+      "name": "W-down-presses-up",
+      "args": [
+        true,
+        "W"
+      ],
+      "expected": {
+        "tag": "Press",
+        "key": "Up"
+      }
+    },
+    {
+      "name": "W-up-releases-up",
+      "args": [
+        false,
+        "W"
+      ],
+      "expected": {
+        "tag": "Release",
+        "key": "Up"
+      }
+    },
+    {
+      "name": "S-down-presses-down",
+      "args": [
+        true,
+        "S"
+      ],
+      "expected": {
+        "tag": "Press",
+        "key": "Down"
+      }
+    },
+    {
+      "name": "S-up-releases-down",
+      "args": [
+        false,
+        "S"
+      ],
+      "expected": {
+        "tag": "Release",
+        "key": "Down"
+      }
+    },
+    {
+      "name": "R-down-restarts",
+      "args": [
+        true,
+        "R"
+      ],
+      "expected": {
+        "tag": "Restart"
+      }
+    },
+    {
+      "name": "R-up-does-nothing",
+      "args": [
+        false,
+        "R"
+      ],
+      "expected": null
     }
   ]
 }