chore: remove playground and backend-mock

.vscode/launch.json

@@ -2,15 +2,6 @@
   "$schema": "https://json.schemastore.org/launchsettings.json",
   "version": "0.2.0",
   "configurations": [
-    {
-      "type": "chrome",
-      "name": "vben admin playground dev",
-      "request": "launch",
-      "url": "http://localhost:5555",
-      "env": { "NODE_ENV": "development" },
-      "sourceMaps": true,
-      "webRoot": "${workspaceFolder}/playground"
-    },
     {
       "type": "chrome",
       "name": "vben admin antd dev",