fix: memory pool alloc mismatch in tests, db_sync SEND_DATA buffer overflow

- test_etcp_router_reconnect, test_etcp_connect, test_stcp_traffic:
  replace u_calloc with memory_pool_alloc for TOPO_SOCKMETA4/TOPO_ADDR4
- db_sync.c: fix req[14] -> req[15] — SEND_DATA request header is 15 bytes
  (type:1 + from:4 + count:2 + vp:4 + want_from:4)

src/routing_layer/topo_node_sqlite.c

@@ -124,9 +124,10 @@ static uint8_t collect_socket_ids(struct TOPO_NODE* ni, uint8_t* sock_ids) {
     return count;
 }
 
-int topo_node_sqlite_node_put(sqlite3* db, struct TOPO_NODEQ* nq, time_t now_sec) {
-    if (!db || !nq || !nq->node) return -1;
-    struct TOPO_NODE* ni = nq->node;
+int topo_node_sqlite_node_put(sqlite3* db, struct TOPO_GROUPS* groups, struct TOPO_GROUP_NODE* nq, time_t now_sec) {
+    if (!db || !nq) return -1;
+    struct TOPO_NODE* ni = topo_node_registry_find(groups, nq->node_id);
+    if (!ni) return -1;
 
     sqlite3_exec(db, "BEGIN", NULL, NULL, NULL);
 
@@ -760,7 +761,7 @@ struct TOPO_NODE* topo_node_sqlite_node_load(sqlite3* db, struct TOPO_GROUPS* gr
 
     struct TOPO_NODE* ni = u_calloc(1, sizeof(struct TOPO_NODE));
     if (!ni) { u_free(name); return NULL; }
-    ni->node_id = node_id; ni->ver = 1; ni->ref_count = 0;
+    ni->node_id = node_id; ni->ver = 1; ni->group_ref_count = 0;
     memcpy(ni->public_key, pubkey, 32); memcpy(ni->ed25519_public_key, ed_pubkey, 32);
     ni->node_name = name;
     ni->v4_addrs = v4_head;