feat(reader): persist Try-it activation in localStorage

marketing-site/components/reader/useActivation.js

@@ -0,0 +1,43 @@
+import { useCallback, useEffect, useMemo, useState } from "react";
+
+function keyFor(id) {
+  return `aibook-demo-activation:${id}`;
+}
+
+/**
+ * Demo-only activation state. Completing a Try-it writes
+ * localStorage key `aibook-demo-activation:<RECIPE-ID>`.
+ */
+export default function useActivation(ids) {
+  const list = useMemo(() => ids, [ids.join("|")]);
+  const [complete, setComplete] = useState(() =>
+    Object.fromEntries(list.map((id) => [id, false]))
+  );
+
+  useEffect(() => {
+    const next = {};
+    list.forEach((id) => {
+      try {
+        next[id] = window.localStorage.getItem(keyFor(id)) === "1";
+      } catch {
+        next[id] = false;
+      }
+    });
+    setComplete(next);
+  }, [list]);
+
+  const toggle = useCallback((id) => {
+    setComplete((prev) => {
+      const value = !prev[id];
+      try {
+        window.localStorage.setItem(keyFor(id), value ? "1" : "0");
+      } catch {
+        /* private mode: still toggle in memory */
+      }
+      return { ...prev, [id]: value };
+    });
+  }, []);
+
+  const count = list.filter((id) => complete[id]).length;
+  return { complete, toggle, count, total: list.length };
+}