feat: add unit tests and CI configuration

vitest.config.ts

@@ -0,0 +1,18 @@
+import { defineConfig } from 'vitest/config'
+import react from '@vitejs/plugin-react'
+import path from 'path'
+
+export default defineConfig({
+  plugins: [react()],
+  test: {
+    environment: 'jsdom',
+    setupFiles: ['./vitest.setup.ts'],
+    include: ['**/__tests__/**/*.test.{ts,tsx}', '**/*.test.{ts,tsx}'],
+    globals: true,
+  },
+  resolve: {
+    alias: {
+      '@': path.resolve(__dirname, '.'),
+    },
+  },
+})