fix: improve doc link navigation and tree display

- Fix link resolution with proper relative/absolute path handling
- Improve link styling with underline decoration
- Hide leaf nodes from tree, only show directories
- Fix log file path for packaged app

docs/api/core/refcounted/GetRefCount.md

@@ -0,0 +1,43 @@
+# RefCounted::GetRefCount
+
+```cpp
+uint32_t GetRefCount() const;
+```
+
+获取当前引用计数。
+
+**描述**
+
+返回当前的引用计数值。由于使用 `std::atomic` 实现，因此是线程安全的。
+
+**返回：** `uint32_t` - 当前引用计数
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+#include <XCEngine/Core/RefCounted.h>
+
+class MyObject : public RefCounted {
+public:
+    void Debug() {
+        printf("RefCount: %u\n", GetRefCount());
+    }
+};
+
+MyObject* obj = new MyObject();
+printf("After create: %u\n", obj->GetRefCount());  // 1
+
+obj->AddRef();
+printf("After AddRef: %u\n", obj->GetRefCount());  // 2
+
+obj->Release();
+printf("After Release: %u\n", obj->GetRefCount()); // 1
+```
+
+## 相关文档
+
+- [RefCounted 总览](refcounted.md) - 返回类总览
+- [AddRef](AddRef.md) - 增加引用计数
+- [Release](Release.md) - 减少引用计数