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/read-write-lock/read-write-lock.md

@@ -0,0 +1,91 @@
+# ReadWriteLock
+
+**命名空间**: `XCEngine::Threading`
+
+**类型**: `class`
+
+**头文件**: `XCEngine/Threading/ReadWriteLock.h`
+
+**描述**: 读写锁，允许多个读者或单个写者
+
+## 概述
+
+`ReadWriteLock` 实现了一个经典的读写锁。它允许多个线程同时持有读锁，但在有写锁时，所有读锁都必须释放，写锁为独占访问。这对于读操作远多于写操作的共享数据非常有效。
+
+### 设计目的
+
+- 提供比普通互斥锁更高的并发性能
+- 允许多个线程同时读取共享数据
+- 确保写入操作时的独占性访问
+- 防止写者饥饿（通过写者优先策略）
+
+### 使用场景
+
+- 读多写少的共享数据访问
+- 需要保护长时间读取的数据结构
+- 数据库、缓存、配置等共享资源访问
+
+## 公共方法
+
+| 方法 | 描述 |
+|------|------|
+| [`ReadWriteLock`](constructor.md) | 构造一个读写锁 |
+| [`~ReadWriteLock`](destructor.md) | 销毁读写锁 |
+| [`ReadLock`](readlock.md) | 获取读锁（支持多个并发读者） |
+| [`ReadUnlock`](readunlock.md) | 释放读锁 |
+| [`WriteLock`](writelock.md) | 获取写锁（独占，阻塞所有读者和写者） |
+| [`WriteUnlock`](writeunlock.md) | 释放写锁 |
+
+## 使用示例
+
+```cpp
+#include "XCEngine/Threading/ReadWriteLock.h"
+#include <thread>
+#include <vector>
+#include <iostream>
+#include <map>
+
+XCEngine::Threading::ReadWriteLock rwLock;
+std::map<std::string, int> sharedCache;
+
+// 读操作（多个线程可同时读）
+int ReadData(const std::string& key) {
+    rwLock.ReadLock();
+    int value = 0;
+    auto it = sharedCache.find(key);
+    if (it != sharedCache.end()) {
+        value = it->second;
+    }
+    rwLock.ReadUnlock();
+    return value;
+}
+
+// 写操作（独占）
+void WriteData(const std::string& key, int value) {
+    rwLock.WriteLock();
+    sharedCache[key] = value;
+    rwLock.WriteUnlock();
+}
+
+int main() {
+    std::vector<std::thread> threads;
+
+    threads.emplace_back(WriteData, "score", 100);
+    threads.emplace_back(ReadData, "score");
+    threads.emplace_back(WriteData, "health", 200);
+    threads.emplace_back(ReadData, "health");
+
+    for (auto& t : threads) {
+        t.join();
+    }
+
+    return 0;
+}
+```
+
+## 相关文档
+
+- [`ReadLock`](readlock.md) - 获取读锁
+- [`ReadUnlock`](readunlock.md) - 释放读锁
+- [`WriteLock`](writelock.md) - 获取写锁
+- [`WriteUnlock`](writeunlock.md) - 释放写锁