feat(web): sync workflow docs from server and persist task artifact in chat

Pass doc_id on task runs, merge server deliverable state by task_key,
fetch controlled document content when opening non-template docs, and
map metadata.artifact after refresh.

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

web/src/api/taskStream.ts

@@ -63,6 +63,7 @@ export function buildTaskRequest(task: TaskRunContext): Record<string, unknown>
   if (task.materials && task.materials.length > 0) {
     body.materials = task.materials;
   }
+  if (task.docId) body.doc_id = task.docId;
   return body;
 }