fix: peers_* table creation + GUI_ERROR to log + cross-connect conn reuse

- chat_core.c: CREATE TABLE IF NOT EXISTS peers_* in ensure_channel_ready
- utun_node.cpp: GUI_ERROR redirected to debug log file via guiDebugFile()
- etcp_connections.c: reuse unindexed outbound conn (peer_node_id==0)
  on cross-connect INIT to avoid 'Can not insert link to socket'

tools/chatgui/transport/utun_node.cpp

@@ -5,6 +5,7 @@
 #include "../../lib/socket_compat.h"
 
 #include "../db/db_manager.h"
+#include "../src/debug_ui.h"
 
 // === C headers ===
 extern "C" {
@@ -205,6 +206,7 @@ void UtunNode::runLoop() {
         debug_enable_file_output(m_debugFile.toUtf8().constData(), 0);
         debug_enable_console(1);
         g_debug_config.thread_marker = 2;
+        guiDebugFile(m_debugFile.toUtf8().constData());
     }
 
     utun_instance_set_tun_init_enabled(0);