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/task-system-config/steal-tasks.md

@@ -0,0 +1,25 @@
+# TaskSystemConfig::stealTasks
+
+```cpp
+bool stealTasks = true
+```
+
+是否启用工作窃取。当启用时，空闲的工作线程可以从其他繁忙线程的任务队列中窃取任务，提高整体吞吐率。
+
+**类型：** `bool`
+
+**默认值：** `true`
+
+**当前状态：** 此配置项当前未实际实现，工作窃取功能不可用。所有工作线程仅从全局任务队列获取任务。
+
+**示例：**
+
+```cpp
+TaskSystemConfig config;
+config.workerThreadCount = 8;
+config.stealTasks = true; // 预留配置项（当前未实现）
+```
+
+## 相关文档
+
+- [TaskSystemConfig 总览](tasksystemconfig.md) - 返回类总览