[feat] add Linux headless mode and interactive console

apps/desktop/src/platform/linux/headless/headless_session.h

@@ -0,0 +1,23 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-09-25
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _HEADLESS_SESSION_H_
+#define _HEADLESS_SESSION_H_
+
+#include <functional>
+
+namespace crossdesk {
+
+// Must run before logging, SDL, Slint or any worker threads are initialized.
+// Automatically selects the user's existing desktop, or supervises a private Xvfb
+// server and the application as children for the duration of a headless session.
+int RunWithLinuxDisplay(int argc, char* argv[],
+                        const std::function<int()>& run_application,
+                        const std::function<bool()>& prepare_headless = {});
+
+}  // namespace crossdesk
+
+#endif