etcp: replace connections linked-list with indexed ll_queue, add state/ref_count lifecycle

- Remove ETCP_CONN.next linked-list, UTUN_INSTANCE.connections list/count
- Unified connections in single ll_queue indexed by peer_node_id (0=pending)
- struct conn_queue_entry { peer_node_id, conn* } for uniform queue data
- Connection lifecycle via etcp.c: create→pending, conn_ready→indexed, close→detach+deferred free
- Close split: phase1 detach from external world, phase2 deferred via uasync_call_soon
- etcp_conn_set_peer_node_id: reindex on ID change (WARN)
- etcp_conn_ref_take/free: blocking close until refcount returns to 0
- Remove chat_connections — use unified connections queue directly
- Update all iteration/search patterns across 40 files (src + tests + chatgui)

src/utun_instance.c

@@ -106,6 +106,9 @@ static int instance_init_common(struct UTUN_INSTANCE* instance, struct UASYNC* u
         DEBUG_ERROR(DEBUG_CATEGORY_CONFIG, "Failed to create networks queue");
         return -1;
     }
+    // Initialize connection queue
+    instance->connections = queue_new(ua, 256, 0, 8, "connections");
+    if (!instance->connections) { DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "Failed to create connections queue"); return -1; }
     struct CFG_NETWORK *net = config->networks;
     while (net) {
         struct ll_entry *entry = queue_entry_new(sizeof(struct NETWORK_ENTRY));
@@ -397,17 +400,17 @@ void utun_instance_destroy(struct UTUN_INSTANCE *instance) {
     instance->etcp_sockets = NULL;
     DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "[INSTANCE_DESTROY] ETCP sockets cleanup complete");
     
-    // Safe cleanup of ETCP connections with NULL pointer checks
-    struct ETCP_CONN* conn = instance->connections;
-    while (conn) {
-        struct ETCP_CONN* next = conn->next;
-        DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "[INSTANCE_DESTROY] Closing connection %p", conn);
-        if (conn) {  // Дополнительная проверка на случай поврежденного списка
-            etcp_connection_close(conn);  // Закрыть соединение (с проверкой NULL внутри)
+    // Cleanup ETCP connections (phase 1 detach + deferred phase 2 via call_soon)
+    {
+        struct ll_entry* entry = instance->connections->head;
+        while (entry) {
+            struct ll_entry* next = entry->next;
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+            if (ce && ce->conn) etcp_connection_close(ce->conn);
+            entry = next;
         }
-        conn = next;
     }
-    instance->connections = NULL;
+    queue_free(instance->connections); instance->connections = NULL;
     DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "[INSTANCE_DESTROY] ETCP connections cleanup complete");
     
     struct PING_CONTEXT* p = instance->pending_pings;
@@ -578,7 +581,7 @@ int utun_instance_init(struct UTUN_INSTANCE *instance) {
         return -1;
     }
     
-    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "Connections initialized successfully, count=%d", instance->connections_count);
+    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "Connections initialized successfully, count=%d", queue_entry_count(instance->connections));
     
     // Initialize control server if configured
     if (instance->config->global.control_sock.ss_family != 0) {
@@ -654,16 +657,15 @@ void utun_instance_diagnose_leaks(struct UTUN_INSTANCE *instance, const char *ph
     }
     
     // Подсчёт ETCP соединений
-    struct ETCP_CONN *conn = instance->connections;
-    while (conn) {
-        report.etcp_connections_count++;
-        // Подсчёт линков в соединениях
-        struct ETCP_LINK *link = conn->links;
-        while (link) {
-            report.etcp_links_count++;
-            link = link->next;
+    {
+        struct ll_entry* entry = instance->connections->head;
+        while (entry) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+            report.etcp_connections_count++;
+            struct ETCP_LINK *link = ce->conn->links;
+            while (link) { report.etcp_links_count++; link = link->next; }
+            entry = entry->next;
         }
-        conn = conn->next;
     }
     
     DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "[LEAK DIAGNOSIS] Phase: %s", phase);
@@ -788,9 +790,12 @@ struct UTUN_INSTANCE *utun_instance_reload(struct UTUN_INSTANCE *instance, struc
     // Clients [client:] and links (link=)
     for (struct CFG_CLIENT *nc = new_config->clients; nc; nc = nc->next) {
         struct ETCP_CONN *conn = NULL;
-        for (struct ETCP_CONN *c = instance->connections; c; c = c->next) {
-            if (strcmp(nc->name, c->name) == 0) {
-                conn = c; break;
+        {
+            struct ll_entry* entry = instance->connections->head;
+            while (entry) {
+                struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+                if (strcmp(nc->name, ce->conn->name) == 0) { conn = ce->conn; break; }
+                entry = entry->next;
             }
         }
         if (!conn) {