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

docs/事故复盘-CK误删与恢复.md

@@ -36,8 +36,8 @@ LoginTask.cookie.isnot(None) & (LoginTask.cookie != "")
 而列表接口序列化时：
 
 ```python
-status=attempt_status or t.status     # 显示的是「最近一次尝试」
-message=(attempt_message if attempt_status else "") or t.message
+status = attempt_status or t.status  # 显示的是「最近一次尝试」
+message = (attempt_message if attempt_status else "") or t.message
 ```
 
 两者不是一回事。生产实测当时有 **752 行**处于「显示 failed、但 cookie 非空」的状态
@@ -46,8 +46,10 @@ message=(attempt_message if attempt_status else "") or t.message
 新加的「清空失败」按**显示状态**筛：
 
 ```python
-or_(and_(attempt_status != "", attempt_status == "failed"),
-    and_(attempt_status == "", status == "failed"))
+or_(
+    and_(attempt_status != "", attempt_status == "failed"),
+    and_(attempt_status == "", status == "failed"),
+)
 ```
 
 于是这 752 行连同其它 success 行一起被选中删除。**这不是单纯的边界疏漏，是把两个

docs/设计-登录任务与CK解耦.md

@@ -131,13 +131,19 @@ cookie_updated_at: Mapped[datetime | None] = mapped_column(UTCDateTime, nullable
 # ── CK 健康状态（原 login_tasks.ck_check_*）──
 ck_check_status: Mapped[str] = mapped_column(String(16), default="", nullable=False)
 ck_check_result: Mapped[dict | None] = mapped_column(JSON, nullable=True)
-ck_checked_at: Mapped[datetime | None] = mapped_column(UTCDateTime, nullable=True, index=True)
+ck_checked_at: Mapped[datetime | None] = mapped_column(
+    UTCDateTime, nullable=True, index=True
+)
 
 # ── 重登调度（原 login_tasks.relogin_*）──
 relogin_attempts: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
-relogin_next_at: Mapped[datetime | None] = mapped_column(UTCDateTime, nullable=True, index=True)
+relogin_next_at: Mapped[datetime | None] = mapped_column(
+    UTCDateTime, nullable=True, index=True
+)
 relogin_last_error: Mapped[str] = mapped_column(String(512), default="", nullable=False)
-relogin_failure_kind: Mapped[str] = mapped_column(String(16), default="", nullable=False)
+relogin_failure_kind: Mapped[str] = mapped_column(
+    String(16), default="", nullable=False
+)
 ```
 
 `login_tasks` 的对应列**本次不动**（既不读写、也不 drop），留到下一次发版再清理 —— 这是回退后路，见 §6、§7。
@@ -366,12 +372,14 @@ db.query(Account)
 **直接消失**（表现为「账号突然没有 CK」，且无从察觉是漏回填）。所以迁移里必须：
 
 ```python
-expected = db.execute(text(
-    "SELECT COUNT(DISTINCT account_id) FROM login_tasks WHERE cookie IS NOT NULL AND cookie <> ''"
-)).scalar()
-actual = db.execute(text(
-    "SELECT COUNT(*) FROM accounts WHERE cookie IS NOT NULL AND cookie <> ''"
-)).scalar()
+expected = db.execute(
+    text(
+        "SELECT COUNT(DISTINCT account_id) FROM login_tasks WHERE cookie IS NOT NULL AND cookie <> ''"
+    )
+).scalar()
+actual = db.execute(
+    text("SELECT COUNT(*) FROM accounts WHERE cookie IS NOT NULL AND cookie <> ''")
+).scalar()
 if actual < expected:
     raise RuntimeError(f"回填不完整：期望 {expected}，实际 {actual}，中止迁移")
 ```

docs/设计-账号详情页与事件历史.md

@@ -71,11 +71,19 @@ class AccountEvent(Base):
     account_id: Mapped[int] = mapped_column(ForeignKey("accounts.id"), index=True)
     event_type: Mapped[str] = mapped_column(String(32), index=True)
     occurred_at: Mapped[datetime] = mapped_column(UTCDateTime, index=True)
-    title: Mapped[str] = mapped_column(String(256), default="")   # 直接可展示
-    amount: Mapped[int | None] = mapped_column(Integer, nullable=True)        # 充值额/消耗积分（有符号）
-    balance_after: Mapped[int | None] = mapped_column(Integer, nullable=True) # 变更后余额
-    detail: Mapped[dict | None] = mapped_column(JSON, nullable=True)          # 精简后的细节（非原始大 JSON）
-    source: Mapped[str] = mapped_column(String(24), default="")   # login/task/audit/manual
+    title: Mapped[str] = mapped_column(String(256), default="")  # 直接可展示
+    amount: Mapped[int | None] = mapped_column(
+        Integer, nullable=True
+    )  # 充值额/消耗积分（有符号）
+    balance_after: Mapped[int | None] = mapped_column(
+        Integer, nullable=True
+    )  # 变更后余额
+    detail: Mapped[dict | None] = mapped_column(
+        JSON, nullable=True
+    )  # 精简后的细节（非原始大 JSON）
+    source: Mapped[str] = mapped_column(
+        String(24), default=""
+    )  # login/task/audit/manual
     source_ref: Mapped[str] = mapped_column(String(96), unique=True)  # 幂等键
     created_at: Mapped[datetime] = mapped_column(UTCDateTime, default=_utcnow)
 ```