feat: add context menu to conversations screen and simplify manage network UI component

lib/features/agents/presentation/screens/agent_network_screen.dart

@@ -151,22 +151,14 @@ class AgentNetworkScreen extends ConsumerWidget {
             width: 0.5),
         borderRadius: BorderRadius.circular(7),
       ),
-      child: Row(
-        children: [
-          const Text(
-            'Manage My Network',
-            style: TextStyle(
-              fontFamily: 'Fractul',
-              fontSize: 14,
-              fontWeight: FontWeight.w600,
-              color: AppColors.primaryDark,
-            ),
-          ),
-          const Spacer(),
-          Icon(Icons.arrow_forward,
-              size: 20,
-              color: AppColors.primaryDark.withValues(alpha: 0.7)),
-        ],
+      child: const Text(
+        'Manage My Network',
+        style: TextStyle(
+          fontFamily: 'Fractul',
+          fontSize: 14,
+          fontWeight: FontWeight.w600,
+          color: AppColors.primaryDark,
+        ),
       ),
     );
   }

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

@@ -200,18 +200,48 @@ class _ConversationsScreenState extends ConsumerState<ConversationsScreen> {
             ),
           ),
           const SizedBox(width: 8),
-          // Three dots menu (outside the search box)
-          GestureDetector(
-            onTap: () {},
-            behavior: HitTestBehavior.opaque,
-            child: const Padding(
-              padding: EdgeInsets.all(4),
-              child: Icon(
-                Icons.more_horiz,
-                size: 22,
-                color: AppColors.primaryDark,
-              ),
+          // Three dots menu
+          PopupMenuButton<String>(
+            icon: const Icon(
+              Icons.more_horiz,
+              size: 22,
+              color: AppColors.primaryDark,
             ),
+            padding: EdgeInsets.zero,
+            onSelected: (value) {
+              switch (value) {
+                case 'mark_all_read':
+                  final conversations =
+                      ref.read(messagingProvider).conversations;
+                  for (final c in conversations) {
+                    if (c.unreadCount > 0) {
+                      ref
+                          .read(messagingProvider.notifier)
+                          .markAsRead(c.id);
+                    }
+                  }
+                  ScaffoldMessenger.of(context).showSnackBar(
+                    const SnackBar(
+                        content: Text('All conversations marked as read')),
+                  );
+                  break;
+                case 'refresh':
+                  ref
+                      .read(messagingProvider.notifier)
+                      .loadConversations();
+                  break;
+              }
+            },
+            itemBuilder: (_) => const [
+              PopupMenuItem(
+                value: 'mark_all_read',
+                child: Text('Mark all as read'),
+              ),
+              PopupMenuItem(
+                value: 'refresh',
+                child: Text('Refresh'),
+              ),
+            ],
           ),
         ],
       ),