Fix back button behavior

fixes #12

app/templates/place.gjs

@@ -77,11 +77,11 @@ export default class PlaceTemplate extends Component {
   navigateBack(place) {
     // The sidebar calls this with null when "Back" is clicked.
     if (place === null) {
-      // If we have history, go back (preserves search state)
-      if (window.history.length > 1) {
+      // If we came from search results, go back in history
+      if (this.mapUi.returnToSearch) {
         window.history.back();
       } else {
-        // Fallback if opened directly
+        // Otherwise just close the sidebar (return to map index)
         this.router.transitionTo('index');
       }
     } else {