keepalive handshake: device_type + keepalive negotiation in UDP/TCP INIT

- Добавлен device_type (1 байт, CLIENT_TYPE_*) в INIT_REQUEST и INIT_RESPONSE
- Добавлен keepalive_interval (2 байта) в INIT_RESPONSE
- STCP handshake расширен с 43 до 46 байт (device_type+keepalive)
- negotiate_keepalive(): оба desktop/server → min, иначе (есть mobile) → max
- keepalive_interval вынесен в UTUN_INSTANCE для использования в handshake
- stcp_client_connect() принимает device_type и keepalive_interval
- peer_device_type/peer_keepalive_interval передаются через stcp_link в ETCP_LINK

tools/chatgui/src/accountlist.cpp

@@ -38,6 +38,8 @@ QString AccountList::addrStr(const void* addr, int family) {
     }
     if (family == 6) {
         const uint16_t* a = (const uint16_t*)addr;
+        int zero = 1; for (int i = 0; i < 8; i++) if (a[i]) { zero = 0; break; }
+        if (zero) return "[::]";
         return QString("%1:%2:%3:%4:%5:%6:%7:%8")
             .arg(ntohs(a[0]), 0, 16).arg(ntohs(a[1]), 0, 16)
             .arg(ntohs(a[2]), 0, 16).arg(ntohs(a[3]), 0, 16)
@@ -336,8 +338,16 @@ void AccountList::updateDetailDisplay() {
             QString lc = (lk.linkState == 3 && lk.linkStatus == 1) ? "#4CAF50" : "#E53935";
             QString left  = QString("%1:%2").arg(addrStr(lk.localAddr.constData(), lk.localFamily)).arg(lk.localPort);
             QString right = QString("%1:%2").arg(addrStr(lk.addr.constData(), lk.family)).arg(lk.port);
-            lines.append(QString("<span style='color:%1;'>●</span> %2 %3 → %4")
-                         .arg(lc, proto, left, right));
+            const char* arrow = lk.isServer
+                ? "<b style='color:#FF9800;font-size:13pt;'>◀</b>"
+                : "<b style='color:#2196F3;font-size:13pt;'>▶</b>";
+            if (lk.localFamily == 6 || lk.family == 6) {
+                lines.append(QString("<span style='color:%1;'>●</span> %2 %3:%4").arg(lc, proto, addrStr(lk.localAddr.constData(), lk.localFamily)).arg(lk.localPort));
+                lines.append(QString("&nbsp;%1 %2:%3").arg(arrow, addrStr(lk.addr.constData(), lk.family)).arg(lk.port));
+            } else {
+                lines.append(QString("<span style='color:%1;'>●</span> %2 %3 %4 %5")
+                             .arg(lc, proto, left, arrow, right));
+            }
         }
         /* DB addresses without live link */
         for (const auto& a : m_detailAddrs) {