feat(HEL-382): 搭建 datahub 底座和盘后正式数据链路

新增独立 xiaobai-datahub 服务（SQLite WAL、Tushare 盘后发布、/v1 契约和管理后台），不改现站页面与数据链路。

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

xiaobai-datahub/datahub/adapters/base.py

@@ -0,0 +1,47 @@
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from typing import Any
+
+
+class AdapterError(RuntimeError):
+    pass
+
+
+class MarketAdapter(ABC):
+    """Uniform adapter: probe / fetch / normalize. Realtime adapters may be stubs in P0."""
+
+    name: str = "base"
+
+    @abstractmethod
+    def probe(self) -> dict[str, Any]:
+        """Liveness check. Must not leak credentials."""
+
+    @abstractmethod
+    def fetch(self, dataset: str, params: dict[str, Any]) -> list[dict[str, Any]]:
+        """Return provider-native rows (pre-canonical)."""
+
+    @abstractmethod
+    def normalize(self, dataset: str, rows: list[dict[str, Any]]) -> list[dict[str, Any]]:
+        """Map provider-native rows onto hub canonical fields."""
+
+
+class ReservedAdapter(MarketAdapter):
+    """Placeholder for a later free/licensed source. Does not pull data in P0."""
+
+    def __init__(self, name: str) -> None:
+        self.name = name
+
+    def probe(self) -> dict[str, Any]:
+        return {
+            "provider": self.name,
+            "configured": False,
+            "state": "reserved",
+            "message": "适配器位已预留，本阶段不接入",
+        }
+
+    def fetch(self, dataset: str, params: dict[str, Any]) -> list[dict[str, Any]]:
+        raise AdapterError(f"{self.name} 适配器本阶段未接入")
+
+    def normalize(self, dataset: str, rows: list[dict[str, Any]]) -> list[dict[str, Any]]:
+        return []