fix(wechat): guard ambiguous memory recall and scheduled task execution

Skip memory injection for short filler messages, demote page-workflow memory
pollution, keep scheduled automation off page.generate, and fail scheduled
tasks that only return clarification instead of deliverables.

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

scheduled-task-worker.mjs

@@ -1,6 +1,7 @@
 import {
   executeScheduledTask,
   formatScheduledTaskDeliveryMessage,
+  looksLikeScheduledTaskNonDelivery,
 } from './scheduled-task-executor.mjs';
 
 export function startScheduledTaskWorker({
@@ -77,6 +78,11 @@ export function startScheduledTaskWorker({
             timeoutMs: executionTimeoutMs,
             logger,
           });
+          if (looksLikeScheduledTaskNonDelivery(result.deliveryText)) {
+            const err = new Error('定时任务未产出可交付结果');
+            err.code = 'SCHEDULED_TASK_NON_DELIVERY';
+            throw err;
+          }
           await deliverTaskResult(task, result.deliveryText);
           await scheduledTaskService.markTaskSucceeded(task, {
             result: {