feat(courier): 小飞侠签收照联调与 OSS 失败回退

补齐 admin 100108 联调入口；track 优先用缓存签收照，上传失败回退 dataURI，日志截断大图。

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

server/dukang-api/src/modules/ops/admin-xiaofeixia.controller.ts

@@ -59,4 +59,9 @@ export class AdminXiaofeixiaController {
   getTrack(@Body() body: XiaofeixiaShipmentQueryDto) {
     return this.service.getTrack(body);
   }
+
+  @Post('get-sign-photos')
+  getSignPhotos(@Body() body: XiaofeixiaShipmentQueryDto) {
+    return this.service.getSignPhotos(body);
+  }
 }

server/dukang-api/src/modules/ops/admin-xiaofeixia.service.ts

@@ -101,6 +101,19 @@ export class AdminXiaofeixiaService {
     return this.wrap(() => this.courier.getTrack(query, options));
   }
 
+  async getSignPhotos(dto: XiaofeixiaShipmentQueryDto) {
+    const query = this.mapShipmentQuery(dto);
+    const options = await this.callOptions();
+    return this.wrap(async () => {
+      const dataUris = await this.courier.getSignPhotos(query, options);
+      return {
+        count: dataUris.length,
+        // 联调预览用：完整 dataURI；日志侧已截断
+        data: dataUris,
+      };
+    });
+  }
+
   private async callOptions() {
     const fromDb = await this.fulfillmentProviderService.resolveDefaultXiaofeixiaConfig();
     return fromDb ? { xiaofeixia: fromDb } : undefined;