fix(overview): 锁定核心高价值套装并修复未查询空值误判

- 高价值套装精确匹配「套装-兔兔白日梦」与「套装-狂战萌兔」，排除头盔/背包/手榴弹散件干扰
- 增加 is_suit_queried_expr，未查询或 NULL 账号严禁误判为双套均可兑换
- 修复前后端序列化空值保持，完善列表与详情页准入状态和判定依据展示
- 新增头盔排除与 NULL 统计防错回归单测，全量通过 689 个用例

tests/test_account_overview.py

@@ -69,15 +69,28 @@ class TestOwnedJudgement:
 
     def test_owned_comes_from_official_records(self):
         got = extract_high_value_goods(
-            [GOODS_AVAILABLE], [RABBIT], [{"commodityName": "破片手榴弹-兔兔白日梦"}]
+            [GOODS_AVAILABLE], [RABBIT], [{"commodityName": "套装-兔兔白日梦"}]
         )
         assert got[0]["owned"] is True
-        assert got[0]["obtained_names"] == ["破片手榴弹-兔兔白日梦"]
+        assert got[0]["obtained_names"] == ["套装-兔兔白日梦"]
 
     def test_not_owned_when_records_empty(self):
         got = extract_high_value_goods([GOODS_AVAILABLE], [RABBIT], [])
         assert got[0]["owned"] is False
 
+    def test_accessories_never_imply_suit_owned(self):
+        """散件配件（手榴弹/头盔/背包）绝不能误判为拥有了高价值套装。"""
+        got = extract_high_value_goods(
+            [GOODS_AVAILABLE],
+            [RABBIT],
+            [
+                {"commodityName": "破片手榴弹-兔兔白日梦"},
+                {"commodityName": "兔兔白日梦头盔"},
+            ],
+        )
+        assert got[0]["owned"] is False
+        assert got[0]["obtained_names"] == []
+
     def test_global_stock_never_implies_owned(self):
         """回归用例：全局库存为 0 或售罄，但 status==0 时，不能推出「这个账号已拥有」"""
         sold_out = {
@@ -99,12 +112,12 @@ class TestOwnedJudgement:
         assert got[0]["owned"] is True
         assert got[0]["count"] == 0  # 全局库存如实展示
 
-    def test_records_match_by_substring_family(self):
-        """同一件东西有多个商品名（套装- / 破片手榴弹-），都要算数。"""
+    def test_records_match_suit_names(self):
+        """兑换记录精确匹配套装名，过滤无关商品。"""
         got = extract_high_value_goods(
             [GOODS_AVAILABLE],
             [RABBIT],
-            [{"commodityName": "破片手榴弹-兔兔白日梦"}, {"commodityName": "别的"}],
+            [{"commodityName": "套装-兔兔白日梦"}, {"commodityName": "别的商品"}],
         )
         assert got[0]["owned"] is True
         assert len(got[0]["obtained_names"]) == 1
@@ -1966,3 +1979,40 @@ class TestHighValueAccountFilters:
         assert hv["unqueried"] == 1  # acc_unqueried
         assert hv["high_points"] == 2  # 500, 800
         assert hv["high_value_broken"] == 1  # acc_broken
+
+    def test_helmet_and_backpack_never_match_over_suit(self):
+        """当商品列表中头盔排在前面时，必须精准匹配到套装-兔兔白日梦，严禁命中头盔。"""
+        items = [
+            {"commodityName": "兔兔白日梦头盔", "commodityId": "helmet_1", "status": 0},
+            {"commodityName": "兔兔白日梦背包", "commodityId": "bag_1", "status": 0},
+            {"commodityName": "套装-兔兔白日梦", "commodityId": "suit_1", "status": 1},
+        ]
+        got = extract_high_value_goods(items, ["套装-兔兔白日梦"], [])
+        assert len(got) == 1
+        assert got[0]["name"] == "套装-兔兔白日梦"
+        assert got[0]["commodity_id"] == "suit_1"
+        assert got[0]["owned"] is True
+        assert got[0]["reason"] == "官方商城显示已达兑换上限"
+
+    def test_null_high_value_owned_not_treated_as_both_available(self):
+        """high_value_owned 为 None 的账号（如被重置过），绝不能误判为双套均可兑换。"""
+        from datetime import datetime, UTC
+        from web.backend.models import Account
+        from web.backend.routers.accounts import accounts_summary
+
+        acc = Account(
+            username="acc_reset_null",
+            password="p",
+            email="e@test.com",
+            email_password="ep",
+            high_value_owned=None,
+            overview_queried_at=datetime.now(UTC),  # 虽然时间不为空，但字段是 None
+        )
+        self.session.add(acc)
+        self.session.commit()
+
+        res = accounts_summary(db=self.session, current=self.admin)
+        hv = res.get("high_value", {})
+        # 绝不计入 both_available，应计入 unqueried
+        assert hv["both_available"] == 2
+        assert hv["unqueried"] == 2