feat: 采购申请新增库管'完结'功能(仿出库审批)

- 后端:approve 接口支持 action=close(已通过→已完结 status 1→4),模型 status_text 支持已完结
- 前端:采购申请状态tab加'已完结',已通过单显示'完结'按钮(库管)

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

@@ -206,7 +206,7 @@ def approve_purchase_request(purchase_id):
         action = data.get('action', 'approve')
         reject_reason = data.get('reject_reason')
 
-        if action not in ('approve', 'reject'):
+        if action not in ('approve', 'reject', 'close'):
             return jsonify({'code': 400, 'msg': '无效的审批操作'}), 400
 
         if action == 'reject' and not reject_reason:
@@ -219,7 +219,7 @@ def approve_purchase_request(purchase_id):
             reject_reason=reject_reason
         )
 
-        msg = '审批通过' if action == 'approve' else '已驳回'
+        msg = '审批通过' if action == 'approve' else ('已驳回' if action == 'reject' else '已完结')
         # ★ Fail-Closed: 审批响应剥离价格字段
         resp = purchase.to_dict()
         for k in ('unit_price', 'total_price', 'tax_rate'):