fix(tauri): add beforeBuildCommand to build frontend assets

Author: Swofty-Developments

crates/tauri-app/tauri.conf.json

@@ -6,7 +6,7 @@
     "devUrl": "http://localhost:5173",
     "frontendDist": "../frontend/dist",
     "beforeDevCommand": "",
-    "beforeBuildCommand": ""
+    "beforeBuildCommand": "cd ../frontend && npm install && npm run build"
   },
   "app": {
     "withGlobalTauri": true,