refactor(status): derive site ready/business_date from PG instead of ingest_state

_ready_flags 改从 PostgreSQL 直接查询（expected_record /
actual_record / baishi_daily_stats），target_date = today − offset。
消除因 ingested_at 日期比对导致的每日零点全站 ready 集体重置。

store.py: 新增 has_data(site, kind, target_date) 查 PG 数据存在性
runtime.py: _ready_flags 返回 (flags, dates) 同源元组，_apply_ready
  同步写入 business_date，修正 ready 与 business_date 不同源导致的
  前端日期标签漂移（如实到就绪却显示'前天'）

Co-Authored-By: Claude <noreply@anthropic.com>

inbound_verify/store.py

@@ -482,6 +482,52 @@ def get_existing_handover_nos(site):
         return set()
 
 
+# ============================== PG 数据存在性查询 ==============================
+
+
+def has_data(site, kind, target_date):
+    """查询 PG：指定站点在 target_date 是否有业务数据。
+    target_date: str 'YYYY-MM-DD' 或 date 对象。
+    返回 (has_rows: bool, count: int)。
+    PG 不可达时返回 (False, 0)，不抛异常——调用方按「未确认存在」处理。
+
+    kind 路由：
+      expected     → expected_record (business_date)
+      actual       → actual_record (scan_time::date)
+      undelivered  → 百世: baishi_daily_stats；4 站: 不单独查（由调用方 expected∧actual 派生）
+    """
+    if site == "百世" and kind == "undelivered":
+        sql = (
+            "SELECT COUNT(*) FROM baishi_daily_stats"
+            " WHERE site = %s AND business_date = %s"
+        )
+        params = (site, target_date)
+    elif kind == "expected":
+        sql = (
+            "SELECT COUNT(*) FROM expected_record"
+            " WHERE site = %s AND business_date = %s"
+        )
+        params = (site, target_date)
+    elif kind == "actual":
+        sql = (
+            "SELECT COUNT(*) FROM actual_record"
+            " WHERE site = %s AND scan_time::date = %s"
+        )
+        params = (site, target_date)
+    else:
+        return (False, 0)
+    try:
+        with _connect(_load_pg_config()["dbname"]) as conn:
+            with conn.cursor() as cur:
+                cur.execute(sql, params)
+                row = cur.fetchone()
+                cnt = int(row[0]) if row else 0
+                return (cnt > 0, cnt)
+    except Exception as e:
+        print(f">> [状态] PG 查询 {site}/{kind}/{target_date} 失败: {e}")
+        return (False, 0)
+
+
 # ============================== 命令行 ==============================