feat(HEL-457): 估值字段级质量门、股票主档每日发布和资金流历史回补

- field_gates 按数据集配置关键字段非空率下限/非有限比例/相对上一批次的塌陷保护，
  字段大面积为空的批次拒发并保留上一正式批次，可读失败原因入 batches.error
- 股票主档交易日 20:00/23:10 自动刷新并发布版本化快照（eod_stocks + publications），
  覆盖新上市/简称变化/N前缀摘除；/v1/stocks 携带 batch_id/published_at，无变化跳过
- moneyflow 历史回补（默认 60 交易日，跳过已发布日期）；未发布点查返回
  available_from/available_to 与 history_not_backfilled 标记，缺失不再静默
- eod-refresh 新增 --force --dataset 安全重发（仍走全部质量门，上一批次可回滚）
- 保持 HEL-435 盘后重试机制；新增 22 项测试覆盖字段拒发/正常通过/旧批保留/
  主档新增改名/资金流覆盖/重复执行幂等

Co-authored-by: multica-agent <github@multica.ai>

xiaobai-datahub/datahub/serving.py

@@ -135,6 +135,29 @@ class V1API:
 
     def stocks(self, updated_since: str, q: dict[str, str]) -> dict[str, Any]:
         limit, offset = self._page(q)
+        today = yyyymmdd(now_shanghai())
+        batch_id, snapshot = self.pipeline.published_stock_snapshot(today)
+        if batch_id:
+            # Formal view: the latest published stock snapshot, with batch
+            # metadata. Filters are applied in-memory on the snapshot.
+            pub = self.pipeline.latest_stocks_publication(today) or {}
+            rows = snapshot
+            if updated_since:
+                rows = []
+            rows = rows[offset: offset + limit]
+            return envelope(
+                rows,
+                {
+                    "tier": "official",
+                    "trade_date": pub.get("trade_date"),
+                    "published_at": pub.get("published_at"),
+                    "source": "tushare:stock_basic",
+                    "batch_id": batch_id,
+                    "stale": False,
+                    "staleness_seconds": 0,
+                    "state": pub.get("state"),
+                },
+            )
         if updated_since:
             rows = self.db.fetchall(
                 "SELECT * FROM stock_master WHERE updated_at >= ? ORDER BY ts_code LIMIT ? OFFSET ?",
@@ -176,7 +199,7 @@ class V1API:
 
     def dataset_status(self, date: str) -> dict[str, Any]:
         trade_date = yyyymmdd(date or now_shanghai())
-        datasets = ("daily", "valuation", "moneyflow", "auction", "index_daily")
+        datasets = ("daily", "valuation", "moneyflow", "auction", "index_daily", "stocks")
         items = []
         for dataset in datasets:
             pub = self.db.fetchone(
@@ -251,7 +274,7 @@ class V1API:
                 raise ApiError(
                     "DATASET_NOT_PUBLISHED",
                     f"{dataset} {start} 尚未发布",
-                    extra={"expected_at": "15:05+08:00"},
+                    extra=self._unpublished_extra(dataset, start),
                 )
             limit, offset = self._page(q)
             sql = f"SELECT * FROM {table} WHERE trade_date = ? AND batch_id = ?"
@@ -281,7 +304,11 @@ class V1API:
             (dataset, start, end),
         )
         if not pubs:
-            raise ApiError("DATASET_NOT_PUBLISHED", f"{dataset} {start}-{end} 尚未发布")
+            raise ApiError(
+                "DATASET_NOT_PUBLISHED",
+                f"{dataset} {start}-{end} 尚未发布",
+                extra=self._unpublished_extra(dataset, end),
+            )
         rows: list[dict[str, Any]] = []
         limit, offset = self._page(q)
         for pub in pubs:
@@ -350,6 +377,20 @@ class V1API:
         offset = max(0, offset)
         return limit, offset
 
+    def _unpublished_extra(self, dataset: str, trade_date: str) -> dict[str, Any]:
+        """Identifiable coverage info: is this a history gap or today-not-yet?"""
+        extra: dict[str, Any] = {"expected_at": "15:05+08:00"}
+        row = self.db.fetchone(
+            "SELECT MIN(trade_date) AS a, MAX(trade_date) AS b FROM publications WHERE dataset = ?",
+            (dataset,),
+        )
+        if row and row.get("a"):
+            extra["available_from"] = row["a"]
+            extra["available_to"] = row["b"]
+            if str(trade_date) < str(row["a"]):
+                extra["reason"] = "history_not_backfilled"
+        return extra
+
     def _official_meta(self, dataset: str, trade_date: str, source: str) -> dict[str, Any]:
         pub = self.db.fetchone(
             "SELECT * FROM publications WHERE dataset = ? AND trade_date = ?",