Add Lua 5.4 scripting integration for dynamic game loading

- Integrated Lua 5.4 engine (32-bit mode for embedded ARM)
- Created LuaGame wrapper class implementing Game interface
- Added C++ bindings exposing renderer, game state, and input to Lua
- Implemented SD card loader for automatic .lua game discovery
- Updated GameLauncher to support std::function for lambda captures
- Made Game class members public for Lua bindings access
- Added example Lua games: counter, snake, bouncing ball
- Included comprehensive API documentation

Games can now be written as .lua text files on SD card and loaded
without recompilation. Build size: 747KB UF2, Lua VM uses ~50-80KB RAM.

lib/game_launcher.h

@@ -8,6 +8,7 @@
 
 #include <stdint.h>
 #include <vector>
+#include <functional>
 #include "input_event.h"
 #include "game.h"
 
@@ -22,8 +23,7 @@ class InputManager;
 struct GameEntry {
     const char* name;           // Display name
     const char* description;    // Short description
-    Game* (*factory)(uint16_t width, uint16_t height, 
-                     LowLevelRenderer* renderer, LowLevelGUI* gui, InputManager* input_manager);  // Factory function
+    std::function<Game*(uint16_t, uint16_t, LowLevelRenderer*, LowLevelGUI*, InputManager*)> factory;  // Factory function
 };
 
 /**
@@ -51,10 +51,10 @@ public:
      * @brief Register a game in the launcher
      * @param name Game display name
      * @param description Short description
-     * @param factory Function pointer to create game instance
+     * @param factory Function or lambda to create game instance
      */
     void register_game(const char* name, const char* description,
-                      Game* (*factory)(uint16_t, uint16_t, LowLevelRenderer*, LowLevelGUI*, InputManager*));
+                      std::function<Game*(uint16_t, uint16_t, LowLevelRenderer*, LowLevelGUI*, InputManager*)> factory);
     
     /**
      * @brief Draw the launcher menu