fix(HEL-412): 刷新降级不再整次失败，并补齐准备中提示

手动刷新与自动补跑共用可用数据判定：日线推算或上一交易日快照记为部分/准备中成功，避免前端误报刷新失败。HTTP JSON 解析错误不再把请求正文写入日志。

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

backend/jobs/refresh.py

@@ -0,0 +1,46 @@
+from __future__ import annotations
+
+from datetime import datetime, time as dt_time
+
+
+def dashboard_has_usable_data(dashboard: dict[str, object]) -> bool:
+    if not isinstance(dashboard, dict) or dashboard.get("status") == "failed":
+        return False
+    meta = dashboard.get("meta") or {}
+    overview = dashboard.get("overview") or {}
+    if isinstance(meta, dict) and (meta.get("trade_date") or meta.get("carried_forward")):
+        return True
+    return bool(isinstance(overview, dict) and overview)
+
+
+def verified_dashboard_result(dashboard: dict[str, object]) -> dict[str, object]:
+    """Manual refresh and automatic catch-up share this rule.
+
+    Derived limit lists or a previous usable snapshot are not whole-job failures.
+    Only a payload with no displayable market data is recorded as failed.
+    """
+    if dashboard_has_usable_data(dashboard):
+        return dashboard
+    meta = dashboard.get("meta") if isinstance(dashboard, dict) else None
+    notice = ""
+    if isinstance(meta, dict):
+        notice = str(meta.get("notice") or meta.get("display_notice") or "")
+    return {
+        "status": "failed",
+        "error": notice or "未获取到可用行情",
+    }
+
+
+def official_catchup_due(today: str, snapshot: dict[str, object]) -> bool:
+    now = datetime.now().astimezone().time().replace(tzinfo=None)
+    if not (dt_time(15, 5) <= now < dt_time(22, 0)):
+        return False
+    meta = snapshot.get("meta") if isinstance(snapshot.get("meta"), dict) else {}
+    actual = str(meta.get("trade_date") or "").replace("-", "")
+    if (
+        actual == today
+        and meta.get("limit_data_source") != "derived"
+        and not meta.get("carried_forward")
+    ):
+        return False
+    return True