stcp: separate v4/v6 sockets, protocol byte in chat addr format, error on bind fail

- stcp_server_create: support AF_INET and AF_INET6 V6ONLY=1 (no dual-stack)
- Add listen_family to stcp_link_config
- init_sockets: return error (not partial) on any bind failure
- add chat_core_sync_my_addresses() call at chatgui startup
- collect_my_addrs: add proto byte (1=UDP, 2=TCP) to binary format
- chat_sync.c JOIN/WELCOME/PEER_UPSERT: read proto byte, write protocol column
- member_sync.c: read proto byte, dynamic protocol bind
- topo_node.c: debug logs for nodeinfo changed detection
- node_config.cpp: type=public for all servers

tools/chatgui-android/app/src/main/java/com/utun/chat/data/ChatRepository.kt

@@ -7,6 +7,7 @@ import java.nio.ByteBuffer
 import java.nio.ByteOrder
 
 const val EVT_NODEINFO_UPDATED = 16
+const val EVT_LINK_STATUS_CHANGED = 17
 
 data class NodeStatus(
     val nodeId: Long = 0,

tools/chatgui-android/app/src/main/java/com/utun/chat/ui/screens/MemberListScreen.kt

@@ -30,8 +30,6 @@ import com.utun.chat.data.MemberAddr
 import com.utun.chat.data.MemberLinks
 import com.utun.chat.data.LinkStatus
 import com.utun.chat.viewmodel.ChatViewModel
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.isActive
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
@@ -52,10 +50,7 @@ fun MemberListScreen(
     LaunchedEffect(selectedMember?.nodeId) {
         val nodeId = selectedMember?.nodeId
         if (nodeId == null) { viewModel.refreshMemberLinks(0); return@LaunchedEffect }
-        while (isActive) {
-            viewModel.refreshMemberLinks(nodeId)
-            delay(1000)
-        }
+        viewModel.refreshMemberLinks(nodeId)
     }
 
     Column(modifier = Modifier.fillMaxSize().navigationBarsPadding()) {

tools/chatgui-android/app/src/main/java/com/utun/chat/viewmodel/ChatViewModel.kt

@@ -196,6 +196,13 @@ class ChatViewModel : ViewModel() {
                 val cur = _currentChannel.value
                 if (cur != null) refreshMembers(cur.id)
             }
+            17 -> { /* LINK_STATUS_CHANGED: [peer_id:8][link_id:1][state:1][status:1][links_up:1][initialized:1] */
+                if (data == null || data.size < 13) return
+                val buf = java.nio.ByteBuffer.wrap(data).order(java.nio.ByteOrder.LITTLE_ENDIAN)
+                val nodeId = buf.getLong()
+                val detail = _selectedMember.value
+                if (detail != null && detail.nodeId == nodeId) refreshMemberLinks(nodeId)
+            }
         }
     }