feat(wechat): add Intent Transaction Layer with unified task schema

Introduce Draft → Confirm → Commit flow for WeChat schedule intents behind
feature flags, plus h5_tasks dual-write/read aggregation and rollout scripts
so reminders and automations get explicit user confirmation before persisting.

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

server.mjs

@@ -320,6 +320,8 @@ let wechatMpService = null;
 let notificationDispatcher = null;
 let scheduleService = null;
 let scheduledTaskService = null;
+let intentDraftService = null;
+let taskUnifiedService = null;
 let feedbackService = null;
 let scheduleReminderWorker = null;
 let scheduledTaskWorker = null;
@@ -362,6 +364,8 @@ async function bootstrapUserAuth() {
     );
     scheduleService = domainServices.scheduleService;
     scheduledTaskService = domainServices.scheduledTaskService;
+    intentDraftService = domainServices.intentDraftService;
+    taskUnifiedService = domainServices.taskUnifiedService;
     pageDataService = domainServices.pageDataService;
     pageDataPublicService =
       domainServices.pageDataPublicService;
@@ -534,6 +538,8 @@ async function bootstrapUserAuth() {
         tkmindProxy,
         scheduleService,
         scheduledTaskService,
+        intentDraftService,
+        taskUnifiedService,
         sessionSnapshotService,
         wechatScheduleLlmConfigService,
         wechatIntentRouter,