restructure project

frontend/vitest.config.ts

@@ -0,0 +1,19 @@
+/// <reference types="vitest/config" />
+import { defineConfig } from 'vite';
+import react from '@vitejs/plugin-react';
+
+export default defineConfig({
+  plugins: [react()],
+  test: {
+    globals: true,
+    environment: 'jsdom',
+    setupFiles: ['./tests/setup.ts'],
+    include: ['src/**/*.test.{ts,tsx}', 'tests/**/*.test.{ts,tsx}'],
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'lcov'],
+      include: ['src/**/*.{ts,tsx}'],
+      exclude: ['src/**/*.test.{ts,tsx}', 'src/main.tsx'],
+    },
+  },
+});