feat: 适配 Lua 5.5.1 最新版 (lua_5.5.1 分支)

- lib/lua 替换为 Lua 5.5.1 官方源码(2026-07 发布, 当前最新)
- luaconf.h LUA_EXTRASPACE 扩为 272 字节(与 5.4.8 同方案)
- C API 完全兼容, 桥接层零改动
- PackagePathConfig 测试沿用跨版本语义断言(5.4+ require 返回 loader data 路径)
- 验证: GTest 44/44 通过

lib/lua/lzio.c

@@ -14,6 +14,7 @@
 
 #include "lua.h"
 
+#include "lapi.h"
 #include "llimits.h"
 #include "lmem.h"
 #include "lstate.h"
@@ -45,17 +46,25 @@ void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
 
 
 /* --------------------------------------------------------------- read --- */
+
+static int checkbuffer (ZIO *z) {
+  if (z->n == 0) {  /* no bytes in buffer? */
+    if (luaZ_fill(z) == EOZ)  /* try to read more */
+      return 0;  /* no more input */
+    else {
+      z->n++;  /* luaZ_fill consumed first byte; put it back */
+      z->p--;
+    }
+  }
+  return 1;  /* now buffer has something */
+}
+
+
 size_t luaZ_read (ZIO *z, void *b, size_t n) {
   while (n) {
     size_t m;
-    if (z->n == 0) {  /* no bytes in buffer? */
-      if (luaZ_fill(z) == EOZ)  /* try to read more */
-        return n;  /* no more input; return number of missing bytes */
-      else {
-        z->n++;  /* luaZ_fill consumed first byte; put it back */
-        z->p--;
-      }
-    }
+    if (!checkbuffer(z))
+      return n;  /* no more input; return number of missing bytes */
     m = (n <= z->n) ? n : z->n;  /* min. between n and z->n */
     memcpy(b, z->p, m);
     z->n -= m;
@@ -66,3 +75,15 @@ size_t luaZ_read (ZIO *z, void *b, size_t n) {
   return 0;
 }
 
+
+const void *luaZ_getaddr (ZIO* z, size_t n) {
+  const void *res;
+  if (!checkbuffer(z))
+    return NULL;  /* no more input */
+  if (z->n < n)  /* not enough bytes? */
+    return NULL;  /* block not whole; cannot give an address */
+  res = z->p;  /* get block address */
+  z->n -= n;  /* consume these bytes */
+  z->p += n;
+  return res;
+}