Refresh WinRT subscriptions before the first incoming value

lib/ble/ble_winrt.cpp

@@ -329,6 +329,15 @@ struct WinState : std::enable_shared_from_this<WinState> {
                         }
                         auto* l = s.incoming(session);
                         if (!l) { if (response) request.RespondWithProtocolError(0x08); return; }
+                        if (!l->opened) {
+                            /* WriteRequested может обогнать posted SubscribedClientsChanged: перечитать реальные CCC. */
+                            auto id = l->id; s.subscriptions(); l = s.link(id);
+                            if (!l || !l->opened) {
+                                DEBUG_WARN(CAT, "BLE WinRT write before mandatory subscriptions link=%llu", (unsigned long long)id);
+                                if (response) request.RespondWithProtocolError(0x08);
+                                return;
+                            }
+                        }
                         auto id = l->id; auto data = bytes(request.Value());
                         DEBUG_TRACE(CAT, "BLE WinRT RX write link=%llu bytes=%zu", (unsigned long long)id, data.size());
                         ble_backend_received(s.owner, id, channel, data.data(), data.size());