etcp: instance-level conn status callbacks (NEW/UP/DOWN/DELETE), fix member online in chatgui

- Add etcp_add_conn_status_cbk/remove/set — unified callback for all connections
- 4 statuses: NEW, UP, DOWN, DELETE — one subscription covers all connections
- Fire points in etcp.c: create→NEW, on_up→UP, on_down→DOWN, close→DELETE
- chat_sync.c: replace cs_on_new_conn+per-conn subs with cs_on_conn_status
- db_sync.c: same migration to instance-level callback
- cs_is_peer_online: use conn->links_up instead of link->link_status (was 0 during INIT handshake)

tools/chatgui/transport/chat_sync.c

@@ -458,8 +458,7 @@ static int cs_is_peer_online(struct UTUN_INSTANCE* inst, uint64_t peer_id) {
     struct ll_entry* e = queue_find_data_by_index(inst->connections, (const uint8_t*)&peer_id);
     if (e) {
         struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data;
-        struct ETCP_LINK* l = ce->conn->links;
-        while (l) { if (l->initialized && l->link_status) return 1; l = l->next; }
+        return ce->conn->initialized && ce->conn->links_up;
     }
     return 0;
 }
@@ -557,6 +556,15 @@ static void cs_on_conn_down(struct ETCP_CONN* conn, void* arg) {
     }
 }
 
+static void cs_on_conn_status(struct ETCP_CONN* conn, int status, void* arg) {
+    switch (status) {
+    case ETCP_CONN_STATUS_UP:   cs_on_conn_up(conn, arg); break;
+    case ETCP_CONN_STATUS_DOWN: cs_on_conn_down(conn, arg); break;
+    default: break;
+    }
+}
+
+#if 0  /* replaced by cs_on_conn_status */
 static void cs_on_new_conn(struct ETCP_CONN* conn, void* arg) {
     (void)arg;
     if (!conn) return;
@@ -564,6 +572,7 @@ static void cs_on_new_conn(struct ETCP_CONN* conn, void* arg) {
     etcp_conn_add_up_cbk(conn, cs_on_conn_up, NULL);
     etcp_conn_add_down_cbk(conn, cs_on_conn_down, NULL);
 }
+#endif
 
 /* ── Periodic refresh from DB ── */
 
@@ -633,17 +642,7 @@ int chat_sync_init(struct UTUN_INSTANCE* inst,
     g_cs = cs;
 
     etcp_bind(inst, ETCP_RT_ID_CHAT_SYNC, chat_sync_recv_cb);
-    etcp_add_new_conn_cbk(inst, cs_on_new_conn, NULL);
-
-    {
-        struct ll_entry* entry = inst->connections->head;
-        while (entry) {
-            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
-            etcp_conn_add_up_cbk(ce->conn, cs_on_conn_up, NULL);
-            etcp_conn_add_down_cbk(ce->conn, cs_on_conn_down, NULL);
-            entry = entry->next;
-        }
-    }
+    etcp_add_conn_status_cbk(inst, cs_on_conn_status, NULL);
 
     cs_refresh_channels(cs);
 
@@ -667,19 +666,10 @@ void chat_sync_destroy(struct UTUN_INSTANCE* inst) {
     cs->initialized = 0; g_cs = NULL;
 
     etcp_unbind(inst, ETCP_RT_ID_CHAT_SYNC);
+    etcp_remove_conn_status_cbk(inst, cs_on_conn_status, NULL);
     if (cs->refresh_timer) { uasync_cancel_timeout(inst->ua, cs->refresh_timer); cs->refresh_timer = NULL; }
     cs_cancel_proto_timers(cs);
 
-    {
-        struct ll_entry* entry = inst->connections->head;
-        while (entry) {
-            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
-            etcp_conn_remove_up_cbk(ce->conn, cs_on_conn_up, NULL);
-            etcp_conn_remove_down_cbk(ce->conn, cs_on_conn_down, NULL);
-            entry = entry->next;
-        }
-    }
-
     for (int i = 0; i < cs->channel_count; i++)
         if (cs->channels[i].peer_ids) u_free(cs->channels[i].peer_ids);
     if (cs->channels) u_free(cs->channels);