feat(promo): generate WeChat mini-program codes on create

Use getwxacodeunlimit with activity id as scene, upload PNG to OSS qrcode/, and show in HQ admin.

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

server/dukang-api/src/integrations/wechat/wechat.disabled.provider.ts

@@ -1,5 +1,5 @@
 import { Injectable, NotImplementedException } from '@nestjs/common';
-import type { IWechatProvider } from './wechat.interface';
+import type { IWechatProvider, WechatWxaCodeUnlimitedInput } from './wechat.interface';
 
 @Injectable()
 export class WechatDisabledProvider implements IWechatProvider {
@@ -54,4 +54,8 @@ export class WechatDisabledProvider implements IWechatProvider {
   parsePayNotification() {
     return this.disabled();
   }
+
+  getWxaCodeUnlimited(_input: WechatWxaCodeUnlimitedInput): Promise<Buffer> {
+    return this.disabled();
+  }
 }