Refactor code structure for improved readability and maintainability

client/vite.config.ts

@@ -0,0 +1,16 @@
+import { defineConfig } from 'vite';
+import react from '@vitejs/plugin-react';
+
+export default defineConfig({
+  plugins: [react()],
+  server: {
+    port: 5173,
+    proxy: {
+      '/api': {
+        target: 'http://localhost:3000',
+        changeOrigin: true,
+        rewrite: (path) => path,
+      },
+    },
+  },
+});