feat: 完善会商产物提交匹配与流式写文件预览

席位流程图按已提交 Markdown 对齐；流式未命名产物不再误请求 artifacts API，并兼容临时文件名路径。同时补强会话流中断识别与 8BF/岗位会商展示。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend-web/src/core/threads/thread-access-error.ts

@@ -62,6 +62,37 @@ export function isThreadNotAccessibleError(message: string): boolean {
   );
 }
 
+export function isAbortLikeError(error: unknown): boolean {
+  if (error instanceof DOMException && error.name === "AbortError") {
+    return true;
+  }
+  if (error instanceof Error && error.name === "AbortError") {
+    return true;
+  }
+  const message = getStreamErrorMessage(error).toLowerCase();
+  return (
+    message.includes("aborterror") ||
+    message.includes("the operation was aborted") ||
+    message.includes("bodystreambuffer")
+  );
+}
+
+export function isTransientStreamTransportError(message: string): boolean {
+  const lowered = message.toLowerCase();
+  return (
+    /failed to fetch/i.test(message) ||
+    lowered.includes("networkerror") ||
+    lowered.includes("network error") ||
+    lowered.includes("load failed") ||
+    lowered.includes("err_connection") ||
+    lowered.includes("err_incomplete") ||
+    lowered.includes("err_network") ||
+    lowered.includes("econnreset") ||
+    lowered.includes("econnaborted") ||
+    /fetch failed/i.test(message)
+  );
+}
+
 /** Build a label for the *current* logged-in identity (email → user_id → 未知). */
 export function buildCurrentUserLabel(): string {
   const auth = getStoredAuth();