feat(script): add voltex_script crate with Lua 5.4 FFI and safe wrapper

Compiles Lua 5.4 from source via cc crate (excluding lua.c/luac.c).
Provides ffi bindings, LuaState safe wrapper, and default engine bindings.
All 9 tests pass (exec, globals, register_fn, voltex_print).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/voltex_script/lua/lundump.h

@@ -0,0 +1,35 @@
+/*
+** $Id: lundump.h $
+** load precompiled Lua chunks
+** See Copyright Notice in lua.h
+*/
+
+#ifndef lundump_h
+#define lundump_h
+
+#include "llimits.h"
+#include "lobject.h"
+#include "lzio.h"
+
+
+/* data to catch conversion errors */
+#define LUAC_DATA	"\x19\x93\r\n\x1a\n"
+
+#define LUAC_INT	0x5678
+#define LUAC_NUM	cast_num(370.5)
+
+/*
+** Encode major-minor version in one byte, one nibble for each
+*/
+#define LUAC_VERSION  (((LUA_VERSION_NUM / 100) * 16) + LUA_VERSION_NUM % 100)
+
+#define LUAC_FORMAT	0	/* this is the official format */
+
+/* load one chunk; from lundump.c */
+LUAI_FUNC LClosure* luaU_undump (lua_State* L, ZIO* Z, const char* name);
+
+/* dump one chunk; from ldump.c */
+LUAI_FUNC int luaU_dump (lua_State* L, const Proto* f, lua_Writer w,
+                         void* data, int strip);
+
+#endif