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.interface.ts

@@ -28,6 +28,17 @@ export type WechatPayNotifyResult = {
   amountFen: number;
 };
 
+export type WechatWxaCodeUnlimitedInput = {
+  /** 最大 32 可见字符，扫码后小程序 onLaunch.options.scene */
+  scene: string;
+  /** 小程序页面路径，如 pages/home/index（不要前导 /） */
+  page?: string;
+  width?: number;
+  checkPath?: boolean;
+  envVersion?: 'release' | 'trial' | 'develop';
+  isHyaline?: boolean;
+};
+
 export interface IWechatProvider {
   isEnabled(): boolean;
 
@@ -81,4 +92,7 @@ export interface IWechatProvider {
     headers: Record<string, string | string[] | undefined>,
     rawBody: string,
   ): Promise<WechatPayNotifyResult>;
+
+  /** 获取不限制的小程序码（PNG Buffer），须服务端调用 */
+  getWxaCodeUnlimited(input: WechatWxaCodeUnlimitedInput): Promise<Buffer>;
 }