Refactor autofocus logic in login dialogs for better platform handling

lib/screens/repeater_hub_screen.dart

@@ -73,7 +73,7 @@ class RepeaterHubScreen extends StatelessWidget {
                     ),
                     const SizedBox(height: 8),
                     Text(
-                      '$repeater.shortPubKeyHex',
+                      repeater.shortPubKeyHex,
                       style: TextStyle(fontSize: 14, color: Colors.grey[600]),
                     ),
                     const SizedBox(height: 8),

lib/widgets/repeater_login_dialog.dart

@@ -322,7 +322,9 @@ class _RepeaterLoginDialogState extends State<RepeaterLoginDialog> {
                     }
                   },
                   onSubmitted: (_) => _handleLogin(),
-                  autofocus: _passwordController.text.isEmpty,
+                  autofocus: !(defaultTargetPlatform == TargetPlatform.android ||
+                      defaultTargetPlatform == TargetPlatform.iOS) &&
+                     _passwordController.text.isEmpty,
                 ),
                 const SizedBox(height: 12),
                 CheckboxListTile(

lib/widgets/room_login_dialog.dart

@@ -293,7 +293,9 @@ class _RoomLoginDialogState extends State<RoomLoginDialog> {
                     ),
                   ),
                   onSubmitted: (_) => _handleLogin(),
-                  //autofocus: _passwordController.text.isEmpty,
+                  autofocus: !(defaultTargetPlatform == TargetPlatform.android ||
+                      defaultTargetPlatform == TargetPlatform.iOS) &&
+                     _passwordController.text.isEmpty,
                 ),
                 const SizedBox(height: 12),
                 CheckboxListTile(