feat: Update app icons and display 'GIF' as message preview for GIF URLs in conversations.

lib/features/messaging/presentation/screens/conversations_screen.dart

@@ -386,6 +386,20 @@ class _ConversationTile extends StatelessWidget {
     required this.onTap,
   });
 
+  static bool _isGifUrl(String text) {
+    final lower = text.trim().toLowerCase();
+    return lower.endsWith('.gif') ||
+        lower.contains('giphy.com/') ||
+        lower.contains('giphy.gif') ||
+        lower.contains('tenor.com/');
+  }
+
+  static String _formatPreview(String text) {
+    if (text.isEmpty) return text;
+    if (_isGifUrl(text)) return 'GIF';
+    return text;
+  }
+
   String _resolveAvatarUrl(String? avatarKey) {
     if (avatarKey == null || avatarKey.isEmpty) return '';
     if (avatarKey.startsWith('http://') || avatarKey.startsWith('https://')) {
@@ -402,7 +416,7 @@ class _ConversationTile extends StatelessWidget {
   Widget build(BuildContext context) {
     final otherParty = conversation.otherParty;
     final avatarUrl = _resolveAvatarUrl(otherParty.avatar);
-    final lastMessage = conversation.lastMessageText ?? '';
+    final lastMessage = _formatPreview(conversation.lastMessageText ?? '');
     final timestamp = _formatTimestamp(conversation.lastMessageAt);
     final unread = conversation.unreadCount;
     final firstLetter = otherParty.name.isNotEmpty