feat(wechat): send rich subscribe welcome with clickable intro and bind links

New followers receive capability overview plus WeChat anchor links for the
deep intro page and account binding instead of exposing raw URLs.

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

wechat-mp.mjs

@@ -42,6 +42,7 @@ import { handleWechatIntentTransaction } from './wechat/handlers/intent-transact
 import { handleWechatScheduledTaskIntent } from './wechat/handlers/scheduled-task.mjs';
 import {
   buildStatusText,
+  buildSubscribeWelcomeText,
   resolveSyncReply,
   shouldHandleSyncReply,
 } from './wechat/handlers/sync-replies.mjs';
@@ -3768,7 +3769,10 @@ export function createWechatMpService({
         body: buildWechatTextReply({
           toUserName: inbound.fromUserName,
           fromUserName: inbound.toUserName,
-          content: `${config.unboundTextPrefix}\n${buildBindUrl()}`,
+          content: buildSubscribeWelcomeText({
+            bindUrl: buildBindUrl(),
+            introUrl: config.subscribeIntroUrl,
+          }),
         }),
       };
     }