feat: x3-backup v1.0.0 initial release

GTK3 backup/snapshot tool using rsync backend.

Features:
- rsync-based snapshots with hardlink delta for space efficiency
- Snapshot sidebar with date-sorted list
- Full file browser with permissions display (name, size, perms, mtime)
- Right-click context menu: Restore file/dir with sudo prompt
- System tray icon: backup status, context menu (show/backup/settings/quit)
- Menu system: File, Backup, System, Help
- Settings dialog: backup destination, source path, retention, exclusions
- Cronjob management: install/remove scheduled backups
- Live Log tab: real-time rsync output during backup
- History Log tab: full log file viewer with color-coded entries
- System Backup mode: full root filesystem backup
- System Restore mode: restore entire system from snapshot
- CLI mode: --backup, --system-backup for cron/headless use
- /mnt always excluded from backups
- Preserves permissions, ACLs, xattrs (-aAX flags)
- Log file: ~/.config/x3-backup/x3-backup.log
- Config: ~/.config/x3-backup/settings.json
- uninstall.sh for clean removal

src/main_window.h

@@ -0,0 +1,106 @@
+#pragma once
+#include <gtk/gtk.h>
+#include <string>
+#include <vector>
+#include <fstream>
+#include "config.h"
+#include "rsync_manager.h"
+#include "snapshot_manager.h"
+#include "system_tray.h"
+#include "settings_dialog.h"
+
+class MainWindow {
+public:
+	MainWindow(Config& config);
+	~MainWindow();
+
+	GtkWidget* widget() const { return window_; }
+	void run();
+	void show();
+	void hide();
+	bool is_visible() const;
+
+	void start_quick_backup();
+
+	SystemTray& tray() { return tray_; }
+
+private:
+	void build_ui();
+	void build_menu();
+	void build_toolbar();
+	void build_sidebar();
+	void build_file_browser();
+	void build_statusbar();
+
+	void refresh_snapshot_list();
+	void load_selected_snapshot();
+	void browse_path(const std::string& snapshot, const std::string& path);
+	void navigate_up();
+
+	void on_backup_clicked();
+	void on_restore_clicked();
+	void on_delete_snapshot_clicked();
+	void on_new_backup_clicked();
+
+	void show_sudo_dialog(std::function<void(const std::string&)> callback);
+	void show_progress_dialog(const std::string& title);
+
+	void install_cronjob();
+	void remove_cronjob();
+	void show_log_window();
+	void append_live_log(const std::string& line, const char* tag = nullptr);
+	void load_log_history();
+
+	static void on_backup(GtkWidget* w, gpointer d);
+	static void on_restore(GtkWidget* w, gpointer d);
+	static void on_delete_snapshot(GtkWidget* w, gpointer d);
+	static void on_new_backup(GtkWidget* w, gpointer d);
+	static void on_settings(GtkWidget* w, gpointer d);
+	static void on_quit(GtkWidget* w, gpointer d);
+	static void on_about(GtkWidget* w, gpointer d);
+	static void on_show_log(GtkWidget* w, gpointer d);
+	static void on_snapshot_selected(GtkListBox* box, GtkListBoxRow* row, gpointer d);
+	static void on_file_row_activated(GtkTreeView* tree, GtkTreePath* path, GtkTreeViewColumn* col, gpointer d);
+	static gboolean on_file_button_press(GtkWidget* widget, GdkEventButton* event, gpointer d);
+	static void on_navigate_up(GtkWidget* w, gpointer d);
+	static void on_system_backup(GtkWidget* w, gpointer d);
+	static void on_system_restore(GtkWidget* w, gpointer d);
+	static void on_install_cron(GtkWidget* w, gpointer d);
+	static void on_remove_cron(GtkWidget* w, gpointer d);
+	static gboolean on_tray_close(GtkWidget* widget, GdkEvent* event, gpointer d);
+
+	Config& config_;
+	RsyncManager rsync_;
+	SnapshotManager snapshots_;
+	SystemTray tray_;
+
+	GtkWidget* window_ = nullptr;
+	GtkWidget* notebook_ = nullptr;
+	GtkWidget* snapshot_listbox_ = nullptr;
+	GtkWidget* file_tree_ = nullptr;
+	GtkWidget* path_entry_ = nullptr;
+	GtkWidget* statusbar_ = nullptr;
+	GtkWidget* progress_bar_ = nullptr;
+	GtkWidget* progress_label_ = nullptr;
+	GtkWidget* progress_window_ = nullptr;
+	GtkWidget* nav_label_ = nullptr;
+
+	GtkListStore* file_store_ = nullptr;
+	GtkWidget* toolbar_ = nullptr;
+	GtkWidget* log_window_ = nullptr;
+	GtkWidget* log_textview_ = nullptr;
+	guint log_timer_ = 0;
+
+	GtkWidget* live_log_textview_ = nullptr;
+	GtkWidget* live_log_label_ = nullptr;
+	GtkWidget* backlog_textview_ = nullptr;
+	GtkWidget* backlog_scrolled_ = nullptr;
+
+	std::string log_path_;
+
+	std::string current_snapshot_;
+	std::string current_path_;
+	std::vector<std::string> path_stack_;
+
+	int col_name = 0, col_size = 1, col_type = 2, col_permissions = 3, col_mtime = 4;
+};