Release 1.0.0: rename to NoMines, add leaderboard, theme support and release metadata

- Rename app/binary/app-id to nomines (io.github.bemagri.nomines), config dir
  moves to ~/.config/nomines with legacy path fallback
- Add persistent best-time leaderboard (Glib::KeyFile)
- Theme-aware board following system light/dark preference
- Beveled 3D cells, confetti win animation, keyboard shortcuts,
  right-click chording, per-difficulty window sizing
- Add AppStream metainfo, validate desktop file and metainfo via meson tests
- Fix license metadata to GPL-3.0-or-later and real homepage

src/window.hpp

@@ -2,8 +2,11 @@
 
 #include <gtkmm.h>
 #include <memory>
+#include <utility>
+#include <vector>
 #include "minefield.hpp"
 #include "board_widget.hpp"
+#include "leaderboard.hpp"
 
 class MainWindow : public Gtk::ApplicationWindow {
 public:
@@ -14,12 +17,13 @@ private:
     // UI Setup
     void setup_header_bar();
     void setup_board();
+    void refresh_leaderboard();
     
     // Actions
     void start_new_game(const GameDifficulty& difficulty);
     void on_game_state_changed();
     bool on_timer_tick();
-    void show_game_over_dialog(bool won);
+    void show_game_over_dialog(bool won, bool new_best, int seconds);
 
     // Widgets
     Gtk::HeaderBar header_bar_;
@@ -27,14 +31,23 @@ private:
     Gtk::MenuButton btn_difficulty_;
     Gtk::Popover menu_difficulty_;
     Gtk::Box box_difficulty_; // Content for popover
-    
+    std::vector<std::pair<GameDifficulty, Gtk::CheckButton*>> difficulty_buttons_;
+
+    Gtk::MenuButton btn_leaderboard_;
+    Gtk::Popover menu_leaderboard_;
+    Gtk::Box box_leaderboard_; // Content for popover
+
     Gtk::Label lbl_time_;
     Gtk::Label lbl_flags_;
     
     BoardWidget board_widget_;
+
+    Leaderboard leaderboard_;
     
     // Game State
     std::shared_ptr<Minefield> minefield_;
     sigc::connection timer_conn_;
+    sigc::connection dialog_timeout_conn_;
     GameDifficulty current_difficulty_ = Minefield::DifficultyEasy;
+    Gtk::MessageDialog* game_over_dialog_ = nullptr;
 };