fix: rollback & pin volar version

Author: sxzz

package.json

@@ -68,8 +68,8 @@
     "@types/node": "^20.11.25",
     "@types/prettier": "^2.7.3",
     "@vitejs/plugin-vue": "^5.0.4",
-    "@volar/jsdelivr": "~2.4.0-alpha.8",
-    "@volar/monaco": "~2.4.0-alpha.8",
+    "@volar/jsdelivr": "2.4.0-alpha.12",
+    "@volar/monaco": "2.4.0-alpha.12",
     "@vue/language-service": "2.0.24",
     "bumpp": "^9.4.0",
     "codemirror": "^5.65.14",