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/debug/filelogsink/log.md

@@ -0,0 +1,25 @@
+# FileLogSink::Log
+
+```cpp
+void Log(const LogEntry& entry) override
+```
+
+将日志条目追加写入文件。根据 `LogEntry` 的各字段格式化日志行，包括时间戳、级别、分类、消息，并追加到文件末尾。
+
+**参数：**
+- `entry` - 日志条目
+
+**复杂度：** O(m)，m 为消息长度
+
+**示例：**
+
+```cpp
+auto fileSink = std::make_unique<XCEngine::Debug::FileLogSink>("logs/app.log");
+XCEngine::Debug::Logger::Get().AddSink(std::move(fileSink));
+// Log 方法由 Logger 在内部调用
+XCEngine::Debug::Logger::Get().Error(XCEngine::Debug::LogCategory::FileSystem, "File not found");
+```
+
+## 相关文档
+
+- [FileLogSink 总览](filelogsink.md) - 返回类总览