fix(wechat): resolve scheduled task cancel via manage LLM instead of hard rules

Use a lightweight LLM over active task lists to pick taskId for cancel,
exclude page.generate from scheduled-task inbound, and remove single-task
auto-cancel so Cursor page generation stays isolated.

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

wechat-mp.mjs

@@ -1634,6 +1634,7 @@ export function createWechatMpService({
   intentDraftService = null,
   taskUnifiedService = null,
   wechatScheduleLlmConfigService = null,
+  wechatScheduledTaskManageLlmConfigService = null,
   llmProviderService = null,
   chatIntentRouter = null,
   wechatIntentRouter = null,
@@ -4159,6 +4160,8 @@ export function createWechatMpService({
             intent,
             user: boundUser,
             scheduledTaskService,
+            wechatScheduledTaskManageLlmConfigService,
+            llmProviderService,
             logger,
           }).catch((err) => {
             logger.warn?.(