Migrate to Vite 7, improve UI (Copy/Download), and enhance API security

vite.config.js

@@ -0,0 +1,23 @@
+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,
+      },
+    },
+  },
+  build: {
+    outDir: 'build',
+  },
+  test: {
+    globals: true,
+    environment: 'jsdom',
+    css: true,
+  },
+});