Clean up emitter listeners and destroy Cytoscape instance on unmount

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/views/Discover/Map/MapPage.vue

@@ -627,6 +627,9 @@ function setActivityBgImage(mapData) {
 })();
 
 onBeforeUnmount(() => {
+  emitter.off("saveModal");
+  emitter.off("leaveFilter");
+  cytoscapeGraph.value?.destroy();
   logId.value = null;
   createFilterId.value = null;
   temporaryData.value = [];