fix(expiry): 已过期资产不再从到期统计中消失，总览页改为到期日历

get_expiring/get_overview 去掉 expiry_date>=today 下界（仅排除已注销）并新增 overdue_count；renewal_service 续费提醒纳入已过期、文案区分已过期N天/今天到期/N天后；dashboard 用到期日历逐条显示具体到期日与倒计时；api.js 新增 Fmt.countdownText 统一文案。

app/services/asset_service.py

@@ -434,6 +434,7 @@ def get_overview(session: Session) -> dict:
     by_status: dict = {}
     abnormal = 0
     expiring_30 = 0
+    overdue = 0
     year_cost = 0.0
     month_cost = 0.0
 
@@ -446,8 +447,13 @@ def get_overview(session: Session) -> dict:
             abnormal += 1
         if expiry_date:
             days = (expiry_date - today).days
-            if 0 <= days <= 30:
-                expiring_30 += 1
+            if status_val != AssetStatus.CANCELLED:
+                # 已过期单独计数：过了续费日却还没处理的资产，比 30 天内的更需要被看到，
+                # 不能因为「不在未来窗口内」就从统计里消失
+                if days < 0:
+                    overdue += 1
+                elif days <= 30:
+                    expiring_30 += 1
             if expiry_date.year == today.year:
                 year_cost += cost
                 if expiry_date.month == today.month:
@@ -459,23 +465,24 @@ def get_overview(session: Session) -> dict:
         "by_status": by_status,
         "abnormal_count": abnormal,
         "expiring_30": expiring_30,
+        "overdue_count": overdue,
         "year_cost": round(year_cost, 2),
         "month_cost": round(month_cost, 2),
     }
 
 
 def get_expiring(session: Session, days: int = 30) -> List[AssetRead]:
-    """N 天内到期资产列表（按剩余天数升序）
+    """N 天内到期资产列表，含已过期未处理的（按剩余天数升序，最紧急在前）
 
-    性能优化：过滤条件下推到 SQL 层，仅查询 [today, today+days] 区间内的资产。
+    过滤条件下推到 SQL 层：到期日上界取 today+days，但不设下界 —— 昨天到期的
+    资产比 30 天后到期的更该出现在倒计时里；只排除已注销资产。
     """
-    today = date.today()
-    deadline = today + timedelta(days=days)
+    deadline = date.today() + timedelta(days=days)
     assets = session.exec(
         select(Asset).where(
             Asset.expiry_date.is_not(None),
-            Asset.expiry_date >= today,
             Asset.expiry_date <= deadline,
+            Asset.status.notin_([AssetStatus.CANCELLED]),
         )
     ).all()
     batch = _get_details_batch(session, assets)