feat(welfare): 完成不活跃清零-邀请金不清 + 预警编排 + worker + admin口径统一

- 清零改两桶(金币 + 折算现金);邀请奖励金物理隔离、不清(产品红线),仅快照入审计
- 预警编排 select_warn_candidates / run_warn_once / run_once(分档 + streak 去重);
  notifier.warn 去掉 invite 参数(邀请金不清、不预警)
- 预警逐用户 try/except 隔离 + run_once 保证预警故障绝不阻塞清零(接真推送前必备)
- 每日 worker inactivity_reset_worker(文件锁 + 北京日守卫 + RUN_HOUR 门槛 + 总闸默认关)
  + main.py lifespan 接线
- admin 最近活跃口径改用共享 activity(移除 last_login_at、纳入 home_view 占位)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/integrations/notifier.py

@@ -15,9 +15,10 @@ logger = logging.getLogger("shagua.inactivity")
 class InactivityNotifier(Protocol):
     channel: str
 
-    def warn(self, *, user_id: int, coin: int, cash_cents: int, invite_cash_cents: int,
+    def warn(self, *, user_id: int, coin: int, cash_cents: int,
              stage: int, days_until_reset: int) -> str:
-        """发预警,返回状态:'sent' / 'failed' / 'placeholder'。"""
+        """发预警(只涉及会被清的金币 + 折算现金;邀请现金不清、不预警)。
+        返回状态:'sent' / 'failed' / 'placeholder'。"""
         ...
 
 
@@ -26,12 +27,11 @@ class LogNotifier:
 
     channel = "log"
 
-    def warn(self, *, user_id: int, coin: int, cash_cents: int, invite_cash_cents: int,
+    def warn(self, *, user_id: int, coin: int, cash_cents: int,
              stage: int, days_until_reset: int) -> str:
         logger.warning(
-            "[inactivity-warn] user=%s coin=%s cash_cents=%s invite_cash_cents=%s "
-            "stage=T-%s days_until_reset=%s",
-            user_id, coin, cash_cents, invite_cash_cents, stage, days_until_reset,
+            "[inactivity-warn] user=%s coin=%s cash_cents=%s stage=T-%s days_until_reset=%s",
+            user_id, coin, cash_cents, stage, days_until_reset,
         )
         return "placeholder"