fix: camera添加mode=scanCode确保QR识别事件触发

Co-Authored-By: Claude <noreply@anthropic.com>

haha-admin-mp/src/pages/replenish/scan.vue

@@ -4,6 +4,7 @@
       class="camera-view"
       device-position="back"
       flash="off"
+      mode="scanCode"
       @scancode="onScanCode"
       @error="onCameraError"
     />