add universal qt-free provider interface (#67)

add universal qt-free provider interface

address review

cpp/logos_provider_object.cpp

@@ -1,7 +1,68 @@
 #include "logos_provider_object.h"
+#include "logos_json_convert.h"
 #include "logos_api.h"
 #include "token_manager.h"
 #include <QDebug>
+#include <QJsonDocument>
+
+// ---------------------------------------------------------------------------
+// LogosProviderObject — universal virtual defaults
+// ---------------------------------------------------------------------------
+
+nlohmann::json LogosProviderObject::callMethodStd(const std::string& /*methodName*/,
+                                                   const nlohmann::json& /*args*/)
+{
+    return nullptr;
+}
+
+std::vector<LogosMethodMetadata> LogosProviderObject::getMethodsStd()
+{
+    return {};
+}
+
+void LogosProviderObject::setEventListenerStd(UniversalEventCallback /*callback*/)
+{
+}
+
+// ---------------------------------------------------------------------------
+// LogosProviderObject — bridge helpers (Qt-free providers delegate here)
+// ---------------------------------------------------------------------------
+
+QVariant LogosProviderObject::callMethodStdBridge(const QString& methodName, const QVariantList& args)
+{
+    nlohmann::json jArgs = nlohmann::json::array();
+    for (const QVariant& a : args)
+        jArgs.push_back(logos::qvariantToNlohmann(a));
+
+    nlohmann::json result = callMethodStd(methodName.toStdString(), jArgs);
+    return logos::nlohmannToQVariant(result);
+}
+
+QJsonArray LogosProviderObject::getMethodsStdBridge()
+{
+    return logos::methodsToJsonArray(getMethodsStd());
+}
+
+void LogosProviderObject::setEventListenerStdBridge(EventCallback callback)
+{
+    setEventListenerStd([callback](const std::string& eventName, const std::string& data) {
+        if (!callback) return;
+        QVariantList qData;
+        QJsonDocument doc = QJsonDocument::fromJson(
+            QByteArray::fromStdString(data));
+        if (doc.isArray()) {
+            for (const QJsonValue& v : doc.array())
+                qData.append(v.toVariant());
+        } else {
+            qData.append(QString::fromStdString(data));
+        }
+        callback(QString::fromStdString(eventName), qData);
+    });
+}
+
+// ---------------------------------------------------------------------------
+// LogosProviderBase
+// ---------------------------------------------------------------------------
 
 void LogosProviderBase::init(void* apiInstance)
 {