Fix build: synchronize Request API, fix GmailSynchronizer, and migrate UI to Qt6 Widgets

src/core/accountsetupdialoglauncher.h

@@ -0,0 +1,30 @@
+#ifndef ACCOUNTSETUPDIALOGLAUNCHER_H
+#define ACCOUNTSETUPDIALOGLAUNCHER_H
+
+#include <QObject>
+#include "models/account.h"
+#include "db/dao/accountdao.h"
+#include "core/synchronizerprovider.h"
+#include "core/eventbus.h"
+#include "core/events.h"
+
+class AccountSetupDialogLauncher : public QObject
+{
+    Q_OBJECT
+public:
+    explicit AccountSetupDialogLauncher(QObject *parent = nullptr);
+    ~AccountSetupDialogLauncher() override = default;
+
+    void launchSetupDialog();
+    void setupAccountManually(const Account &account);
+
+signals:
+    void accountSetupStarted();
+    void accountSetupCompleted(const Account &account);
+    void accountSetupFailed(const QString &errorMessage);
+
+private:
+    void initializeSynchronizer(const Account &account);
+};
+
+#endif // ACCOUNTSETUPDIALOGLAUNCHER_H