Refine render junctions guidance

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/routes/chat.ts

@@ -20,8 +20,6 @@ import {
   type SupportedModel,
 } from "./chatStream.js";
 
-const persistentRenderRefPattern = /^res-[a-z0-9-]+$/i;
-
 const payloadSchema = z.object({
   message: z.string().min(1).max(10000),
   session_id: z.string().max(128).optional(),
@@ -69,13 +67,6 @@ export const buildChatRouter = (
       return;
     }
 
-    if (!persistentRenderRefPattern.test(renderRef)) {
-      res.status(400).json({
-        message: "render_ref must be a persistent ref like res-..., not a file path",
-      });
-      return;
-    }
-
     const result = await resultReferenceStore.getFullAuthorized(renderRef, {
       actorKey: toActorKey(userId),
       clientSessionId,