feat: harden bootstrap and add tests

vitest.config.ts

@@ -0,0 +1,18 @@
+import { defineConfig } from 'vitest/config';
+import react from '@vitejs/plugin-react';
+import { fileURLToPath } from 'node:url';
+
+export default defineConfig({
+  plugins: [react()],
+  test: {
+    environment: 'jsdom',
+    globals: true,
+    setupFiles: ['./vitest.setup.ts'],
+    css: false,
+  },
+  resolve: {
+    alias: {
+      '@': fileURLToPath(new URL('./src', import.meta.url)),
+    },
+  },
+});