chore(frontend): scaffold Vite React TypeScript application

frontend-s2s/vitest.config.ts

@@ -0,0 +1,12 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  test: {
+    environment: "jsdom",
+    execArgv: process.allowedNodeEnvironmentFlags.has("--no-experimental-webstorage")
+      ? ["--no-experimental-webstorage"]
+      : [],
+    setupFiles: ["./src/test/setup.ts"],
+    restoreMocks: true,
+  },
+});