fix: improve doc link navigation and tree display

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docs/api/core/filewriter/Flush.md

@@ -0,0 +1,45 @@
+# FileWriter::Flush
+
+```cpp
+bool Flush();
+```
+
+刷新缓冲区。
+
+**描述**
+
+将缓冲区中的数据强制写入磁盘，确保数据持久化。在写入大量数据后应调用此方法以确保数据已保存。
+
+**返回：** `bool` - 是否刷新成功
+
+**复杂度：** O(1)
+
+**示例：**
+
+```cpp
+#include <XCEngine/Core/FileWriter.h>
+#include <string>
+
+using namespace XCEngine::Core;
+
+FileWriter writer("output.txt");
+if (writer.IsOpen()) {
+    // 写入大量数据
+    for (int i = 0; i < 1000; i++) {
+        writer.Write("Line ");
+        writer.Write(std::to_string(i).c_str());
+        writer.Write("\n");
+    }
+    
+    // 刷新确保数据写入磁盘
+    writer.Flush();
+    
+    // 数据已安全保存
+    writer.Close();
+}
+```
+
+## 相关文档
+
+- [FileWriter 总览](filewriter.md) - 返回类总览
+- [Write](Write.md) - 写入数据