fix: 修复长文档分页与滚动同步

apps/web/tests/paged-break-token.test.ts

@@ -0,0 +1,35 @@
+import { describe, expect, it } from "vitest";
+import { resolveBreakTokenElement } from "../src/paged-break-token";
+
+describe("Paged.js 分页断点", () => {
+  it("直接返回元素断点", () => {
+    const element = {
+      nodeType: 1,
+      parentElement: null
+    } as unknown as Element;
+
+    expect(resolveBreakTokenElement(element)).toBe(element);
+  });
+
+  it("文本断点使用父元素继续查找", () => {
+    const parentElement = {} as Element;
+    const textNode = {
+      nodeType: 3,
+      parentElement
+    } as unknown as Node;
+
+    expect(resolveBreakTokenElement(textNode)).toBe(parentElement);
+  });
+
+  it("安全跳过空断点和无父元素节点", () => {
+    const detachedTextNode = {
+      nodeType: 3,
+      parentElement: null
+    } as unknown as Node;
+
+    expect(resolveBreakTokenElement(undefined)).toBeUndefined();
+    expect(
+      resolveBreakTokenElement(detachedTextNode)
+    ).toBeUndefined();
+  });
+});