Add sender avatar display and member list enhancements in chat group

lib/components/group/chat_group_content.dart

@@ -381,15 +381,53 @@ class _ChatGroupContentState extends State<ChatGroupContent> {
       textColor = isDark ? Colors.white : Colors.black87;
     }
 
+    // Trouver le membre qui a envoyé le message pour récupérer sa photo
+    final senderMember = widget.group.members.firstWhere(
+      (m) => m.userId == message.senderId,
+      orElse: () => null as dynamic,
+    ) as dynamic;
+
     return Align(
       alignment: isMe ? Alignment.centerRight : Alignment.centerLeft,
       child: GestureDetector(
         onLongPress: () => _showMessageOptions(context, message, isMe, currentUserId),
-        child: Container(
+        child: Padding(
+          padding: EdgeInsets.symmetric(
+            horizontal: 8,
+            vertical: 4,
+          ),
+          child: Row(
+            mainAxisAlignment: isMe ? MainAxisAlignment.end : MainAxisAlignment.start,
+            crossAxisAlignment: CrossAxisAlignment.end,
+            children: [
+              // Avatar du sender (seulement pour les autres messages)
+              if (!isMe) ...[
+                CircleAvatar(
+                  radius: 16,
+                  backgroundImage: (senderMember != null && 
+                                   senderMember.profilePictureUrl != null && 
+                                   senderMember.profilePictureUrl!.isNotEmpty)
+                      ? NetworkImage(senderMember.profilePictureUrl!)
+                      : null,
+                  child: (senderMember == null || 
+                         senderMember.profilePictureUrl == null || 
+                         senderMember.profilePictureUrl!.isEmpty)
+                      ? Text(
+                          message.senderName.isNotEmpty 
+                              ? message.senderName[0].toUpperCase() 
+                              : '?',
+                          style: const TextStyle(fontSize: 12),
+                        )
+                      : null,
+                ),
+                const SizedBox(width: 8),
+              ],
+              
+              Container(
                 margin: const EdgeInsets.symmetric(vertical: 4),
                 padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
                 constraints: BoxConstraints(
-            maxWidth: MediaQuery.of(context).size.width * 0.7,
+                  maxWidth: MediaQuery.of(context).size.width * 0.65,
                 ),
                 decoration: BoxDecoration(
                   color: bubbleColor,
@@ -454,6 +492,9 @@ class _ChatGroupContentState extends State<ChatGroupContent> {
                   ],
                 ),
               ),
+            ],
+          ),
+        ),
       ),
     );
   }
@@ -642,11 +683,26 @@ class _ChatGroupContentState extends State<ChatGroupContent> {
             itemCount: widget.group.members.length,
             itemBuilder: (context, index) {
               final member = widget.group.members[index];
+              final initials = member.pseudo.isNotEmpty
+                  ? member.pseudo[0].toUpperCase()
+                  : (member.firstName.isNotEmpty 
+                      ? member.firstName[0].toUpperCase() 
+                      : '?');
+              
               return ListTile(
                 leading: CircleAvatar(
-                  child: Text(member.pseudo.substring(0, 1).toUpperCase()),
+                  backgroundImage: (member.profilePictureUrl != null && 
+                                   member.profilePictureUrl!.isNotEmpty)
+                      ? NetworkImage(member.profilePictureUrl!)
+                      : null,
+                  child: (member.profilePictureUrl == null || member.profilePictureUrl!.isEmpty)
+                      ? Text(initials)
+                      : null,
                 ),
                 title: Text(member.pseudo),
+                subtitle: member.role == 'admin' 
+                    ? const Text('Administrateur', style: TextStyle(fontSize: 12))
+                    : null,
               );
             },
           ),