Update Yarn to 4.9.4

Signed-off-by: Sora Morimoto <[email protected]>

Author: smorimoto

package.json

@@ -77,7 +77,7 @@
     "typedoc": "0.28.11",
     "vitest": "3.2.4"
   },
-  "packageManager": "[email protected].2",
+  "packageManager": "[email protected].4",
   "engines": {
     "node": ">=20"
   },