feat: 适配 Lua 5.2.4 (lua_5.2.4 分支)

- lib/lua 替换为 Lua 5.2.4 官方源码; CMakeLists 补 lbitlib.c(5.2 linit 注册 bit32)、删 lutf8lib.c(5.2 无此文件)
- I/O 重定向机制改造: 5.2 无 lua_getextraspace → iopath 指针存入
  Registry 固定索引(IOPATH_REG_IDX=1), 回调经 get_iopath() 取回,
  free_lua 时释放 —— 该方案同样适用于更低版本
- typed interop 版本自适应: capture_result() 的 lua_isinteger 分支用
  #if LUA_VERSION_NUM >= 503 包裹, 5.2 及以下所有数字统一 CJT_NUM
- 测试跨版本适配: PackagePathConfig 接受 require 的两种返回语义;
  typed 数值断言 EXPECT_INT_OR_NUM 宏兼容有无 integer 子类型;
  大整数保真断言仅对 5.3+ 生效(5.2 经 double 必然丢精度)
- 验证: GTest 44/44 通过

test/test_lua_cj_api.cpp

@@ -282,7 +282,12 @@ TEST_F(LuaCjApiTest, PackagePathConfig) {
     
     EXPECT_EQ(ret, 0) << "Require failed, maybe pkgpath not set correctly. Errno: " << get_errno();
     char* res = getresult(runner);
-    EXPECT_STREQ(res, lib_path.c_str());
+    // 跨版本语义适配：
+    //  - Lua 5.3 的 require 返回 1 个值（模块本身），run() 读栈顶得模块返回值 "LoadedViaPkgPath"
+    //  - Lua 5.4+ 的 require 返回 2 个值（模块 + loader data），run() 读栈顶得 loader data（文件路径）
+    // 两者都表明 require 经 pkgpath 成功定位并加载了模块
+    EXPECT_TRUE(strcmp(res, lib_path.c_str()) == 0 || strcmp(res, "LoadedViaPkgPath") == 0)
+        << "unexpected require result: " << (res ? res : "(null)");
 }
 
 // ==================== 新增测试：doString 功能 ====================
@@ -487,13 +492,21 @@ TEST_F(LuaCjApiTest, CallFunctionAfterCleanup) {
 }
 
 // ==================== typed interop 测试（v0.2.2）====================
+// 版本自适应：Lua 5.3+ 有 integer 子类型（CJT_INT），5.2 及以下所有数字均为
+// number（CJT_NUM）。数值断言用 INT_OR_NUM 宏兼容两种情况。
+#if LUA_VERSION_NUM >= 503
+#define EXPECT_INT_OR_NUM(type) EXPECT_EQ(type, CJT_INT)
+#else
+// 5.2 及以下：整型结果也报为 CJT_NUM，且 lua_tostring(10.0) 输出 "10"
+#define EXPECT_INT_OR_NUM(type) EXPECT_EQ(type, CJT_NUM)
+#endif
 
 // 整型参数直通：Lua 收到 integer，返回 integer+1，仓颉侧读回 Int64
 TEST_F(LuaCjApiTest, TypedCallInt) {
     ASSERT_EQ(loadfunction(runner, get_script_path("func_typed_add.lua").c_str(), "inc"), 0);
 
     EXPECT_EQ(callfunction_int(runner, "inc", 41), 0);
-    EXPECT_EQ(result_type(runner), CJT_INT);
+    EXPECT_INT_OR_NUM(result_type(runner));
     EXPECT_EQ(result_int(runner), 42);
     // 字符串形式同步可用（向后兼容）
     EXPECT_STREQ(getresult(runner), "42");
@@ -506,7 +519,12 @@ TEST_F(LuaCjApiTest, TypedCallNum) {
     EXPECT_EQ(callfunction_num(runner, "mul", 4.0), 0);
     EXPECT_EQ(result_type(runner), CJT_NUM);
     EXPECT_DOUBLE_EQ(result_num(runner), 10.0);
+#if LUA_VERSION_NUM >= 503
     EXPECT_STREQ(getresult(runner), "10.0");
+#else
+    // 5.2 的 %.14g 格式化把 10.0 输出为 "10"
+    EXPECT_STREQ(getresult(runner), "10");
+#endif
 }
 
 // 布尔参数直通：返回逻辑非，读回 Bool
@@ -529,7 +547,7 @@ TEST_F(LuaCjApiTest, TypedCallVoid) {
     ASSERT_EQ(loadfunction(runner, get_script_path("func_typed_void.lua").c_str(), "forty_two"), 0);
 
     EXPECT_EQ(callfunction_void(runner, "forty_two"), 0);
-    EXPECT_EQ(result_type(runner), CJT_INT);
+    EXPECT_INT_OR_NUM(result_type(runner));
     EXPECT_EQ(result_int(runner), 42);
 }
 
@@ -539,13 +557,21 @@ TEST_F(LuaCjApiTest, TypedEchoRoundTrip) {
 
     // int 往返
     EXPECT_EQ(callfunction_int(runner, "echo", -123456789LL), 0);
-    EXPECT_EQ(result_type(runner), CJT_INT);
+    EXPECT_INT_OR_NUM(result_type(runner));
     EXPECT_EQ(result_int(runner), -123456789LL);
 
-    // 大整数（超过 double 精确表示范围）往返
+    // 大整数（超过 double 精确表示范围）往返：
+    // 仅 Lua 5.3+（integer 类型）可保真；5.2 及以下经 double 必然丢精度
+#if LUA_VERSION_NUM >= 503
     EXPECT_EQ(callfunction_int(runner, "echo", 9007199254740993LL), 0);
-    EXPECT_EQ(result_type(runner), CJT_INT);
+    EXPECT_INT_OR_NUM(result_type(runner));
     EXPECT_EQ(result_int(runner), 9007199254740993LL);
+#else
+    EXPECT_EQ(callfunction_int(runner, "echo", 9007199254740993LL), 0);
+    EXPECT_EQ(result_type(runner), CJT_NUM);
+    // 经 double 往返，精度丢失为可预期值
+    EXPECT_EQ(result_int(runner), (long long)(double)9007199254740993LL);
+#endif
 
     // num 往返
     EXPECT_EQ(callfunction_num(runner, "echo", 3.14159), 0);
@@ -592,7 +618,7 @@ TEST_F(LuaCjApiTest, TypedRunVariants) {
 
     // int
     EXPECT_EQ(run_int(runner, path.c_str(), 777), 0);
-    EXPECT_EQ(result_type(runner), CJT_INT);
+    EXPECT_INT_OR_NUM(result_type(runner));
     EXPECT_EQ(result_int(runner), 777);
 
     // num
@@ -638,7 +664,7 @@ TEST_F(LuaCjApiTest, TypedAndStringCoexist) {
 TEST_F(LuaCjApiTest, TypedStateAfterCleanup) {
     ASSERT_EQ(loadfunction(runner, get_script_path("func_typed_void.lua").c_str(), "v"), 0);
     EXPECT_EQ(callfunction_void(runner, "v"), 0);
-    EXPECT_EQ(result_type(runner), CJT_INT);
+    EXPECT_INT_OR_NUM(result_type(runner));
 
     EXPECT_EQ(cleanup(runner), 0);