[fix] make Xfce optional with separate Linux deb packages, refs #106

apps/desktop/src/version_checker/linux_update_download.h

@@ -0,0 +1,29 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-10-08
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _LINUX_UPDATE_DOWNLOAD_H_
+#define _LINUX_UPDATE_DOWNLOAD_H_
+
+#include <filesystem>
+#include <string>
+
+#include <nlohmann/json_fwd.hpp>
+
+#include "app_version.h"
+
+namespace crossdesk {
+
+// Uses package-name beside the executable, so source builds cannot inherit an
+// unrelated system installation's variant. Missing/invalid downloads open the
+// release list rather than silently offering a different package or old release.
+std::string LinuxUpdateDownloadUrl(const nlohmann::json& manifest,
+                                   const VersionInfo& latest,
+                                   const std::string& architecture,
+                                   const std::filesystem::path& executable_dir);
+
+}  // namespace crossdesk
+
+#endif