docs(tests): clarify workspace and legacy model test coverage

tests/board-directory.test.mjs

@@ -21,6 +21,7 @@ test('missing parents and corrupt cycles remain accessible without recursive loo
  const roots=boardDirectory([board('orphan','missing'),board('a','b'),board('b','a')]);assert.deepEqual(roots.map(item=>item.board.id),['orphan','a','b']);assert.ok(roots.every(item=>item.children.length===0));
 });
 // 非递增 next_offset 明确拒绝；已经 abort 的信号由请求替身抛回，加载器不得吞掉取消。
+// 取消样本在请求开始前触发，不验证分页中途取消或真实 fetch 是否停止下载。
 test('directory rejects non-advancing pagination and propagates aborts',async()=>{
  await assert.rejects(loadBoardDirectory(async()=>({items:[],next_offset:0}),'w'),/invalid_pagination/);
  const controller=new AbortController();controller.abort();await assert.rejects(loadBoardDirectory(async(_path,options)=>{options.signal.throwIfAborted();},'w',controller.signal),{name:'AbortError'});

tests/canvas-frames.test.mjs

@@ -93,6 +93,7 @@ test("deleting a frame keeps its content and undo restores membership", () => {
 });
 
 // hidden/fixed/scaled 标签、名称与 frameId 往返保存，frame 渲染层序为 -1，设置历史可撤销。
+// 此处核对模型字段，不挂载 FrameNode，也不证明缩放时屏幕字号/视觉层序已通过浏览器检查。
 test("all label modes, frame names and memberships survive save/restore and settings undo", () => {
   const { frame, member, document } = seeded();
   member.data.frameId = frame.id;

tests/canvas-geometry.test.mjs

@@ -35,6 +35,7 @@ test("card types inherit common element transforms and add branching; plain text
 });
 
 // 五种旋转角度乘八方向 handle，检查受影响尺寸和相反局部锚点世界坐标保持不变。
+// 这是40组确定性样本，未模拟 DOM/CSS zoom 或实际指针捕获；失败定位以坐标不变量为准。
 test("all eight handles resize cards while retaining the opposite local anchor, including rotated cards", () => {
   const directions = ["top", "right", "bottom", "left", "top-left", "top-right", "bottom-left", "bottom-right"];
   for (const rotation of [0, 37, 90, 180, 270]) {

tests/canvas-style.test.mjs

@@ -11,6 +11,7 @@ import { resizeFromPointer } from "../src/lib/canvas-geometry.ts";
 function seeded() { return { ...emptyCanvas(), nodes: [makeCanvasNode("text", { x: 100, y: 200 })] }; }
 
 // 从同一父节点分别创建 text/script/image，检查连线端口、图片源、快照往返，再用一次 replace 历史整体撤销。
+// 图片只传符合字符串语法的 data URL，没有上传或图片解码；该断言不验证文件内容可显示。
 test("branch type selection creates the chosen text, script or uploaded image and keeps the link in one undo step", () => {
   for (const kind of ["text", "script", "image"]) {
     const original = seeded();

tests/workspace.test.mjs

@@ -130,7 +130,7 @@ test("renaming reads the latest version and preserves description and content",
   assert.equal(renamed.version, 8);
 });
 
-// 空白或超过 100 字符的标题在请求前拒绝；用 assert.fail 确保没有任何 API 调用。
+// 空白和101个“字”（UTF-8共303字节）在请求前拒绝；这是300字节上限样本，不是任意文本100字符上限。
 test("rename rejects empty or oversized names without any API calls", async () => {
   for (const name of ["   ", "字".repeat(101)]) {
     await assert.rejects(renameBoard(() => assert.fail("unexpected API call"), "space", "board", name), /invalid_title/);