added vite config

frontend/src/vite-env.d.ts

@@ -0,0 +1,12 @@
+/// <reference types="vite/client" />
+
+// Define types for environment variables
+interface ImportMetaEnv {
+  readonly VITE_APP_TITLE: string
+  readonly ENABLE_PRO: string
+  // more env variables...
+}
+
+interface ImportMeta {
+  readonly env: ImportMetaEnv
+}