Fix peer dropdown layout and announcement timing

- Move peer dropdown next to bitchat title
- Add immediate peer announcement on connection
- Fix iOS menu chevron visibility with platform-specific styling
- Force UI updates for join/leave messages
- Add peers to active list immediately on connection
- Remove all announcement delays for instant name resolution

bitchat/ViewModels/ChatViewModel.swift

@@ -252,6 +252,9 @@ extension ChatViewModel: BitchatDelegate {
         )
         messages.append(systemMessage)
         print("[DEBUG] Added join message, total messages: \(messages.count)")
+        
+        // Force UI update
+        objectWillChange.send()
     }
     
     func didDisconnectFromPeer(_ peerID: String) {
@@ -265,6 +268,9 @@ extension ChatViewModel: BitchatDelegate {
         )
         messages.append(systemMessage)
         print("[DEBUG] Added leave message, total messages: \(messages.count)")
+        
+        // Force UI update
+        objectWillChange.send()
     }
     
     func didUpdatePeerList(_ peers: [String]) {