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/task-system-config.md

@@ -0,0 +1,36 @@
+# TaskSystemConfig
+
+**命名空间**: `XCEngine::Threading`
+
+**类型**: `struct`
+
+**头文件**: `XCEngine/Threading/TaskSystemConfig.h`
+
+**描述**: 任务系统配置结构体，用于初始化 TaskSystem 的行为参数。
+
+## 结构体成员
+
+| 成员 | 类型 | 描述 | 默认值 |
+|------|------|------|--------|
+| [`workerThreadCount`](worker-thread-count.md) | `uint32_t` | 工作线程数量（0=自动检测 CPU 核心数） | 0 |
+| [`enableTaskProfiling`](enable-task-profiling.md) | `bool` | 启用任务性能分析（当前未使用） | true |
+| [`stealTasks`](steal-tasks.md) | `bool` | 启用工作窃取（当前未实现） | true |
+| [`maxTaskQueueSize`](max-task-queue-size.md) | `uint32_t` | 最大任务队列大小（当前未强制限制） | 1024 |
+| [`threadStackSize`](thread-stack-size.md) | `uint32_t` | 线程栈大小（当前未使用，0=系统默认） | 0 |
+
+## 使用示例
+
+```cpp
+TaskSystemConfig config;
+config.workerThreadCount = std::thread::hardware_concurrency();
+config.enableTaskProfiling = true;
+config.stealTasks = true;
+config.maxTaskQueueSize = 2048;
+
+TaskSystem::Get().Initialize(config);
+```
+
+## 相关文档
+
+- [TaskSystem](../task-system/task-system.md) - 任务系统
+- [../threading/threading.md](../threading.md) - 模块总览