fix(pl): 司机回执缺品牌数量时仍保存单据，并按业务结果提示成败。

未填写品牌数量不再拦截照片和备注；已填写的品牌数量仍校验。小程序在 HTTP 200 的业务失败下不再弹出保存成功。

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

backend/app/api/pl/public_transport.py

@@ -46,6 +46,7 @@ from app.schemas.pl.transport import (
 )
 from app.services.pl_dibang_bridge_service import plan_has_load_stop
 from app.services.pl_feedback_brand_qty import (
+    driver_feedback_enforces_brand,
     persist_transport_product_feedback,
     require_brand_qtys_if_needed,
 )
@@ -796,7 +797,7 @@ def save_public_driver_stop_feedback(
                     required_brand_id=plan_product.brand_id if plan_product else None,
                     actual_qty=actual_qty,
                     rows=brand_qtys,
-                    enforce=True,
+                    enforce=driver_feedback_enforces_brand(brand_qtys),
                 )
             except ValueError as exc:
                 return error_response(400, str(exc))