Refactor code for improved readability and null safety in various files Also updated PR to allow login via map.

lib/screens/chat_screen.dart

@@ -763,9 +763,18 @@ class _ChatScreenState extends State<ChatScreen> {
 
   void _openMessagePath(Message message, Contact contact) {
     final connector = context.read<MeshCoreConnector>();
-    final fourByteHex = message.fourByteRoomContactKey.map((b) => b.toRadixString(16).padLeft(2, '0')).join().toUpperCase();
+    final fourByteHex = message.fourByteRoomContactKey
-    final senderName =
+        .map((b) => b.toRadixString(16).padLeft(2, '0'))
-        message.isOutgoing ? (connector.selfName ?? 'Me') : widget.contact.type == advTypeRoom ? "${contact.name} [$fourByteHex]" : widget.contact.name;
+        .join()
+        .toUpperCase();
+    final String senderName;
+    if (message.isOutgoing) {
+      senderName = connector.selfName ?? 'Me';
+    } else if (widget.contact.type == advTypeRoom) {
+      senderName = "${contact.name} [$fourByteHex]";
+    } else {
+      senderName = widget.contact.name;
+    }
     final pathMessage = ChannelMessage(
       senderKey: null,
       senderName: senderName,
@@ -831,6 +840,7 @@ class _ChatScreenState extends State<ChatScreen> {
                 leading: const Icon(Icons.chat),
                 title: const Text('Open Chat'),
                 onTap: () {
+                  Navigator.pop(sheetContext);
                   _openChat(context, contact);
                 },
               ),
@@ -977,20 +987,12 @@ class _MessageBubble extends StatelessWidget {
                         fallbackTextColor: textColor.withValues(alpha: 0.7),
                       )
                     else
-                      if(!isOutgoing)
                       Text(
                         messageText,
                         style: TextStyle(
                           color: textColor,
                         ),
                       ),
-                      if(isOutgoing)
-                        Text(
-                          message.text,
-                          style: TextStyle(
-                            color: textColor,
-                          ),
-                        ),
                     if (isOutgoing && message.retryCount > 0) ...[
                       const SizedBox(height: 4),
                       Text(

lib/screens/map_screen.dart

@@ -18,6 +18,7 @@ import 'channels_screen.dart';
 import 'chat_screen.dart';
 import 'contacts_screen.dart';
 import '../widgets/repeater_login_dialog.dart';
+import '../widgets/room_login_dialog.dart';
 import 'repeater_hub_screen.dart';
 import 'settings_screen.dart';
 
@@ -572,6 +573,25 @@ class _MapScreenState extends State<MapScreen> {
     );
   }
 
+  void _showRoomLogin(BuildContext context, Contact room) {
+    showDialog(
+      context: context,
+      builder: (context) => RoomLoginDialog(
+        room: room,
+        onLogin: (password) {
+          // Navigate to chat screen after successful login
+          context.read<MeshCoreConnector>().markContactRead(room.publicKeyHex);
+          Navigator.push(
+            context,
+            MaterialPageRoute(
+              builder: (context) => ChatScreen(contact: room),
+            ),
+          );
+        },
+      ),
+    );
+  }
+
   void _showNodeInfo(BuildContext context, Contact contact) {
     showDialog(
       context: context,
@@ -624,6 +644,14 @@ class _MapScreenState extends State<MapScreen> {
                 },
                 child: const Text('Manage Repeater'),
               ),
+            if (contact.type == advTypeRoom)
+              TextButton(
+                onPressed: () {
+                  Navigator.pop(context);
+                  _showRoomLogin(context, contact);
+                },
+                child: const Text('Join Room'),
+              ),
         ],
       ),
     );

lib/storage/message_store.dart

@@ -87,7 +87,9 @@ class MessageStore {
       reactions: (json['reactions'] as Map<String, dynamic>?)?.map(
         (key, value) => MapEntry(key, value as int),
       ) ?? {},
-      fourByteRoomContactKey: Uint8List.fromList(base64Decode(json['fourByteRoomContactKey'] as String)),
+      fourByteRoomContactKey: json['fourByteRoomContactKey'] != null
+          ? Uint8List.fromList(base64Decode(json['fourByteRoomContactKey'] as String))
+          : null,
     );
   }
 }