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/lua/ltm.h

@@ -0,0 +1,103 @@
+/*
+** $Id: ltm.h $
+** Tag methods
+** See Copyright Notice in lua.h
+*/
+
+#ifndef ltm_h
+#define ltm_h
+
+
+#include "lobject.h"
+
+
+/*
+* WARNING: if you change the order of this enumeration,
+* grep "ORDER TM" and "ORDER OP"
+*/
+typedef enum {
+  TM_INDEX,
+  TM_NEWINDEX,
+  TM_GC,
+  TM_MODE,
+  TM_LEN,
+  TM_EQ,  /* last tag method with fast access */
+  TM_ADD,
+  TM_SUB,
+  TM_MUL,
+  TM_MOD,
+  TM_POW,
+  TM_DIV,
+  TM_IDIV,
+  TM_BAND,
+  TM_BOR,
+  TM_BXOR,
+  TM_SHL,
+  TM_SHR,
+  TM_UNM,
+  TM_BNOT,
+  TM_LT,
+  TM_LE,
+  TM_CONCAT,
+  TM_CALL,
+  TM_CLOSE,
+  TM_N		/* number of elements in the enum */
+} TMS;
+
+
+/*
+** Mask with 1 in all fast-access methods. A 1 in any of these bits
+** in the flag of a (meta)table means the metatable does not have the
+** corresponding metamethod field. (Bit 7 of the flag is used for
+** 'isrealasize'.)
+*/
+#define maskflags	(~(~0u << (TM_EQ + 1)))
+
+
+/*
+** Test whether there is no tagmethod.
+** (Because tagmethods use raw accesses, the result may be an "empty" nil.)
+*/
+#define notm(tm)	ttisnil(tm)
+
+
+#define gfasttm(g,et,e) ((et) == NULL ? NULL : \
+  ((et)->flags & (1u<<(e))) ? NULL : luaT_gettm(et, e, (g)->tmname[e]))
+
+#define fasttm(l,et,e)	gfasttm(G(l), et, e)
+
+#define ttypename(x)	luaT_typenames_[(x) + 1]
+
+LUAI_DDEC(const char *const luaT_typenames_[LUA_TOTALTYPES];)
+
+
+LUAI_FUNC const char *luaT_objtypename (lua_State *L, const TValue *o);
+
+LUAI_FUNC const TValue *luaT_gettm (Table *events, TMS event, TString *ename);
+LUAI_FUNC const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o,
+                                                       TMS event);
+LUAI_FUNC void luaT_init (lua_State *L);
+
+LUAI_FUNC void luaT_callTM (lua_State *L, const TValue *f, const TValue *p1,
+                            const TValue *p2, const TValue *p3);
+LUAI_FUNC void luaT_callTMres (lua_State *L, const TValue *f,
+                            const TValue *p1, const TValue *p2, StkId p3);
+LUAI_FUNC void luaT_trybinTM (lua_State *L, const TValue *p1, const TValue *p2,
+                              StkId res, TMS event);
+LUAI_FUNC void luaT_tryconcatTM (lua_State *L);
+LUAI_FUNC void luaT_trybinassocTM (lua_State *L, const TValue *p1,
+       const TValue *p2, int inv, StkId res, TMS event);
+LUAI_FUNC void luaT_trybiniTM (lua_State *L, const TValue *p1, lua_Integer i2,
+                               int inv, StkId res, TMS event);
+LUAI_FUNC int luaT_callorderTM (lua_State *L, const TValue *p1,
+                                const TValue *p2, TMS event);
+LUAI_FUNC int luaT_callorderiTM (lua_State *L, const TValue *p1, int v2,
+                                 int inv, int isfloat, TMS event);
+
+LUAI_FUNC void luaT_adjustvarargs (lua_State *L, int nfixparams,
+                                   struct CallInfo *ci, const Proto *p);
+LUAI_FUNC void luaT_getvarargs (lua_State *L, struct CallInfo *ci,
+                                              StkId where, int wanted);
+
+
+#endif