chore: final Minor polish — export filename/test断言, downloadBlob 类型/清理, plan docs

address review Minors: drop redundant filename replace, assert 暂无消息,
tighten downloadBlob return type + try/finally, fix plan group time-picker wording.

Co-Authored-By: Claude <noreply@anthropic.com>

yunkes/src/api/client.ts

@@ -42,11 +42,11 @@ export function getJson<T>(url: string, params?: Record<string, unknown>): Promi
   return http.get(url, { params }) as unknown as Promise<T>
 }
 
-/** 以 blob 下载（用于 HTML 导出等二进制/文本附件下载）。返回建议文件名（来自 content-disposition，缺失则 undefined）。 */
+/** 以 blob 下载（用于 HTML 导出等二进制/文本附件下载）。返回固定文件名（响应拦截器丢失 content-disposition 头）。 */
 export async function downloadBlob(
   url: string,
   params?: Record<string, unknown>,
-): Promise<string | undefined> {
+): Promise<string> {
   const res = await http.get(url, { params, responseType: 'blob' })
   const blob = res as unknown as Blob
   // 从响应头取文件名（拦截器只解包 body，需用 raw 拦截；此处 res 已是 blob，header 丢失 → 用固定名）
@@ -56,8 +56,11 @@ export async function downloadBlob(
   a.href = objUrl
   a.download = filename
   document.body.appendChild(a)
-  a.click()
-  document.body.removeChild(a)
-  URL.revokeObjectURL(objUrl)
+  try {
+    a.click()
+  } finally {
+    document.body.removeChild(a)
+    URL.revokeObjectURL(objUrl)
+  }
   return filename
 }