chore: add @tailwindcss/postcss and PostCSS setup for Tailwind v4

composables/useFixtureIO.ts

@@ -0,0 +1,25 @@
+import { useCounterStore } from '~/stores/counter'
+
+export type AppSnapshot = {
+  counter: { count: number }
+}
+
+export function useFixtureIO() {
+  const exportAll = (): AppSnapshot => {
+    const counter = useCounterStore()
+    return {
+      counter: { count: counter.count }
+    }
+  }
+
+  const importAll = (snapshot: AppSnapshot) => {
+    const counter = useCounterStore()
+    if (snapshot?.counter) {
+      counter.$patch({ count: snapshot.counter.count ?? 0 })
+    }
+  }
+
+  return { exportAll, importAll }
+}
+
+