refactor: improve test infrastructure and fix OpenGL GLAD initialization

- Rename D3D12Enum.h to D3D12Enums.h for naming consistency
- Fix OpenGL unit test GLAD initialization by using gladLoadGL()
  instead of gladLoadGLLoader(wglGetProcAddress) for fallback support
- Migrate remaining tests to use gtest_discover_tests for granular
  test discovery (math, core, containers, memory, threading, debug,
  components, scene, resources, input, opengl)
- Remove obsolete TEST_RESOURCES_DIR and copy_directory commands
  from OpenGL unit test CMakeLists (minimal/Res doesn't exist)
- Update TEST_SPEC.md with performance metrics and per-module
  build/test commands for faster development workflow
- Update CMake path references to use lowercase paths

docs/api/threading/lambda-task/constructor.md

@@ -0,0 +1,41 @@
+# LambdaTask::LambdaTask
+
+```cpp
+explicit LambdaTask(Func&& func, TaskPriority priority = TaskPriority::Normal)
+```
+
+构造 Lambda 任务对象，将可调用对象包装为 ITask。
+
+**模板参数：**
+- `Func` - 可调用对象类型
+
+**参数：**
+- `func` - 要封装的可调用对象（lambda、函数指针、std::function 等）
+- `priority` - 任务优先级，默认值为 TaskPriority::Normal
+
+**返回：** 无
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+// 使用 std::function lambda
+auto task = std::make_unique<LambdaTask<std::function<void()>>>(
+    []() { printf("Task executed\n"); },
+    TaskPriority::High
+);
+TaskSystem::Get().Submit(std::move(task));
+
+// 配合 TaskSystem::Submit 的重载直接使用
+TaskSystem::Get().Submit(
+    std::make_unique<LambdaTask<std::function<void()>>>(
+        []() { ProcessData(); },
+        TaskPriority::Critical
+    )
+);
+```
+
+## 相关文档
+
+- [LambdaTask 总览](lambdatask.md) - 返回类总览