Add Lua scripting support to desktop emulator

- Created emulator-specific lua_game_emulator.cpp using filesystem instead of FatFS
- Created lua_game_loader_emulator.cpp to scan games/lua_examples directory
- Updated CMakeLists.txt to include Lua 5.4 engine and bindings
- Updated to SFML 3.0 API compatibility (event handling, sprite initialization)
- Updated Game class to use public members for Lua bindings
- Updated GameLauncher to use std::function for lambda captures
- Added continuous 60 FPS rendering for smooth display
- Emulator now loads and runs all three example Lua games

emulator/low_level_display_sfml.h

@@ -1,5 +1,6 @@
 #pragma once
 #include <SFML/Graphics.hpp>
+#include <optional>
 
 class LowLevelDisplaySFML {
 public:
@@ -8,12 +9,12 @@ public:
     void draw_buffer(const uint8_t* bit_buffer);
     void refresh();
     bool isOpen() const;
-    bool pollEvent(sf::Event& event);
+    std::optional<sf::Event> pollEvent();
     void close();
 private:
     int width, height;
     sf::RenderWindow window;
     sf::Texture texture;
-    sf::Sprite sprite;
+    std::optional<sf::Sprite> sprite;
     std::vector<uint8_t> framebuffer;
 };