chatgui: invite link connect flow + GUI_ERROR always-on diagnostics

- debug_ui.h: remove NDEBUG guard so GUI_ERROR works in Release builds
- invite_link.h/cpp: add error field to InviteData with specific failure reason
- joindialog: show exact decode error in QLabel instead of generic message
- chat_sync: implement invite connect flow (CHANNEL_INFO_REQ/RESP, JOIN, WELCOME)
- topo_node_sqlite: node/address table init and lookup
- utun_node: getInviteAddresses fallback from ETCP sockets
- minor fixes in mainwindow, chat_core, gui_bridge

tools/chatgui/src/joindialog.cpp

@@ -77,9 +77,9 @@ JoinDialog::JoinDialog(UtunNode* node, DbManager* db, QWidget* parent)
 
     connect(m_linkEdit, &QLineEdit::returnPressed, this, &JoinDialog::onConnectClicked);
 
-    gui_bridge_set_connect_result_cb([](uint64_t nodeId, int result) {
+    gui_bridge_set_connect_result_cb([](uint64_t nodeId, uint64_t channelId, int result) {
         JoinDialog* dlg = qobject_cast<JoinDialog*>(QApplication::activeModalWidget());
-        if (dlg) dlg->onConnectResult(nodeId, result);
+        if (dlg) dlg->onConnectResult(nodeId, channelId, result);
     });
 }
 
@@ -105,8 +105,12 @@ void JoinDialog::onConnectClicked() {
 
     setStatus("Parsing link...");
     InviteData d = decodeInviteLink(link);
-    if (d.channelId.isEmpty() || d.pubkey.size() != 32) {
-        setStatus("Invalid invite link.", true);
+    if (!d.error.isEmpty()) {
+        setStatus("Invalid invite link: " + d.error, true);
+        return;
+    }
+    if (d.pubkey.size() != 32) {
+        setStatus(QString("Invalid invite link: pubkey is %1 bytes (need 32)").arg(d.pubkey.size()), true);
         return;
     }
     if (d.addrs.isEmpty()) {
@@ -124,6 +128,7 @@ void JoinDialog::onConnectClicked() {
     nodeId &= 0x7FFFFFFFFFFFFFFFULL;
 
     m_pendingNodeId = nodeId;
+    m_pendingChannelId = d.channelId;
     m_connecting = true;
     m_connectBtn->setEnabled(false);
     m_linkEdit->setReadOnly(true);
@@ -138,21 +143,23 @@ void JoinDialog::onConnectClicked() {
         addrsBuf.append(static_cast<char>(a.port & 0xFF));
     }
 
-    QByteArray chId = d.channelId.toUtf8();
     int addrCount = d.addrs.size();
 
-    chat_sync_connect_from_invite(nodeId,
+    chat_sync_connect_from_invite(d.channelId, nodeId,
         (const uint8_t*)d.pubkey.constData(),
-        (const uint8_t*)addrsBuf.constData(), addrCount,
-        (const uint8_t*)chId.constData(), chId.size());
+        (const uint8_t*)addrsBuf.constData(), addrCount);
 }
 
-void JoinDialog::onConnectResult(uint64_t nodeId, int result) {
+void JoinDialog::onConnectResult(uint64_t nodeId, uint64_t channelId, int result) {
     if (!m_connecting || nodeId != m_pendingNodeId) return;
 
     if (result == 0) {
-        setStatus("Connected successfully!");
-        QTimer::singleShot(800, this, [this] { accept(); });
+        setStatus("Connected! Waiting for channel data...");
+        QTimer::singleShot(800, this, [this] {
+            QString cid = QString::number(m_pendingChannelId);
+            emit joined(cid);
+            accept();
+        });
     } else {
         m_connecting = false;
         m_connectBtn->setEnabled(true);