feat(borrow,outbound): 申请预检按需显示审批人——默认不显示，命中需审批才出现并必选

- 后端新增 /borrow/request/check-approval 与 /outbound/request/check-approval 预检接口
- 申请弹窗默认隐藏审批人；提交前预检：命中需审批→显示审批人并红字列物料、未选拦截；未命中→隐藏并直接提交(approver=null)
- 申请 items 补传 base_id 供后端 ID 精确判定

inventory-backend/app/api/v1/transactions.py

@@ -311,6 +311,25 @@ def close_borrow_request(request_id):
         return jsonify({'code': 500, 'msg': f'服务器内部错误: {str(e)}'}), 500
 
 
+# --- 借库申请预检（判断所选物料是否需审批，驱动前端是否显示审批人） ---
+@trans_bp.route('/borrow/request/check-approval', methods=['POST'])
+@jwt_required()
+@permission_required('op_borrow_apply')
+def check_borrow_approval():
+    try:
+        data = request.get_json() or {}
+        items = data.get('items', []) or []
+        from app.services.approval_control import resolve_approval_control
+        need_approval, flagged = resolve_approval_control(items)
+        return jsonify({
+            "code": 200, "msg": "success",
+            "data": {"need_approval": need_approval, "materials": flagged}
+        }), 200
+    except Exception as e:
+        import traceback; traceback.print_exc()
+        return jsonify({"code": 500, "msg": f"预检失败: {str(e)}"}), 500
+
+
 # --- 获取借库审批单列表 ---
 @trans_bp.route('/borrow/request', methods=['GET'])
 @jwt_required()