Refresh sidebar folders when the advanced conversation list closes

Creating/renaming/deleting a folder in ConversationListView only ever
updated its own local @State — the sidebar has a separate folders
array that was only refreshed by onAppear or conversation-change
triggers, so a folder created in the modal didn't show up in the
sidebar until the next app launch. Sidebar now reloads when
showConversations transitions to false (the modal closing).

oAI/Views/Main/SidebarView.swift

@@ -167,6 +167,11 @@ struct SidebarView: View {
         }
         .onChange(of: chatViewModel.currentConversationName) { loadData() }
         .onChange(of: chatViewModel.messages.count) { loadData() }
+        .onChange(of: chatViewModel.showConversations) { _, isShowing in
+            // Folders/conversations created, renamed, or deleted in the advanced
+            // conversation list modal live in its own @State — refresh ours once it closes.
+            if !isShowing { loadData() }
+        }
     }
 
     @ViewBuilder