[refactor] share file transfer core across desktop and mobile

libs/controller/include/mobile_file_transfer_session.h

@@ -0,0 +1,24 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-10-09
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _MOBILE_FILE_TRANSFER_SESSION_H_
+#define _MOBILE_FILE_TRANSFER_SESSION_H_
+
+#include "file_transfer_core.h"
+
+namespace crossdesk::mobile_controller {
+
+// Mobile pickers provide disposable copies and expose completed files through
+// their existing per-transfer directories. The transfer engine is shared with PC.
+class FileTransferSession : public file_transfer::Session {
+ public:
+  FileTransferSession(Send send, Progress progress)
+      : Session(std::move(send), std::move(progress), {true, true, 4}) {}
+};
+
+}  // namespace crossdesk::mobile_controller
+
+#endif