feat: add explicit confirmation for back button and refresh in archives

src/App.tsx

@@ -635,21 +635,26 @@ export default function App() {
     
     const handleBeforeUnload = (e: BeforeUnloadEvent) => {
       if (inArchive) {
+        const message = 'Are you sure you want to leave? Your current archive session will be cleared.';
         e.preventDefault();
-        e.returnValue = ''; // Trigger browser confirmation dialog
+        e.returnValue = message; // Standard for most browsers
+        return message; // For some older browsers
       }
     };
 
     const handlePopState = (e: PopStateEvent) => {
       if (inArchive) {
-        // Instead of going back, just exit the archive
+        if (window.confirm('Exit current archive and return to explorer?')) {
+          // Exit the archive
           setAllPosts([]);
           setAllStories([]);
           setCurrentArchive(null);
           resetProfileState();
-        // Stay on the same page
+        } else {
+          // Push the state back so the URL stays the same and we can intercept again
           window.history.pushState(null, '');
         }
+      }
     };
 
     if (inArchive) {