feat: add curriculum management admin dashboard with AI generation and draft approval workflows

src/hooks/useBeforeUnload.js

@@ -0,0 +1,22 @@
+import { useEffect } from 'react';
+
+/**
+ * Prevent accidental tab/window closure while a long-running operation
+ * is in progress. Shows the browser's native "Leave site?" confirmation.
+ *
+ * @param {boolean} active — true while the operation is running
+ */
+export function useBeforeUnload(active) {
+  useEffect(() => {
+    if (!active) return;
+
+    const handler = (e) => {
+      e.preventDefault();
+      // Legacy browsers require returnValue to be set
+      e.returnValue = '';
+    };
+
+    window.addEventListener('beforeunload', handler);
+    return () => window.removeEventListener('beforeunload', handler);
+  }, [active]);
+}