feat: Implement push notification suppression for active chats, prevent duplicate self-messages, update the chat typing indicator, and add back buttons to static screens.

lib/core/widgets/app_bottom_nav_bar.dart

@@ -15,7 +15,8 @@ int _currentTabIndex(BuildContext context) {
     return 1;
   }
   if (location.startsWith('/profile')) return 3;
-  return 0; // home and everything else
+  if (location == '/home') return 0;
+  return -1; // other pages (about, contact, faq, etc.) — no tab highlighted
 }
 
 class AppBottomNavBar extends ConsumerWidget {