Fix ETCP test: server connection registration and packet handling

- etcp_connections.c: Add incoming server connections to instance->connections list
- test_etcp_simple_traffic.c: Fix ETCP_FRAGMENT handling in check_packet_received()
- test_etcp_simple_traffic.c: Fix packet size check (ETCP adds headers to payload)
- Reduced debug verbosity in ll_queue.c and debug_config.c

src/etcp_connections.c

@@ -546,6 +546,11 @@ static void etcp_connections_read_callback(int fd, void* arg) {
             char buf[128];
             addr_to_string(&addr, buf, sizeof(buf));
             DEBUG_DEBUG(DEBUG_CATEGORY_CONNECTION, "New connection from %s peer_id=%ld etcp=%p", buf, peer_id, conn);
+            // Add connection to instance list
+            conn->next = e_sock->instance->connections;
+            e_sock->instance->connections = conn;
+            e_sock->instance->connections_count++;
+            DEBUG_INFO(DEBUG_CATEGORY_CONNECTION, "Added incoming connection %p to instance, total count: %d", conn, e_sock->instance->connections_count);
             }
         else {// check keys если существующее подключение
             if (memcmp(conn->crypto_ctx.peer_public_key, sc.peer_public_key, SC_PUBKEY_SIZE)) { errorcode=5; DEBUG_ERROR(DEBUG_CATEGORY_CRYPTO, "etcp_connections_read_callback: peer key mismatch for node %llu", (unsigned long long)peer_id); goto ec_fr; }// коллизия - peer id совпал а ключи разные.