data_provider: 新增链上指标模块 (btc_netflow/stablecoin_supply/etf_flow/mvrv_zscore)

- onchain_metrics.py: 独立模块，CoinMetrics/CoinGecko/Farside 免费数据源
- main.py: 集成后台线程 + REST API (/api/onchain/metrics, /latest, /available)
- requirements.txt: 添加 requests 依赖
- 5分钟自动刷新，CSV 落盘到 data/onchain/

data_provider/main.py

@@ -24,6 +24,12 @@ from fastapi.responses import HTMLResponse
 import uvicorn
 from technical.util import resample_to_interval
 
+from onchain_metrics import (
+    OnchainMetricsManager,
+    api_keys_from_env,
+    create_onchain_router,
+)
+
 # docker compose logs --tail=200
 # docker compose down && docker compose build --no-cache && docker compose up -d
 
@@ -1132,6 +1138,13 @@ def create_app(provider: DataProvider) -> FastAPI:
     """构造 FastAPI 应用：lifespan 内同步 initialize 并启动后台拉数；WebSocket 实时推送。"""
     ws_manager = WebSocketManager()
 
+    # 初始化链上指标模块
+    onchain_manager = OnchainMetricsManager(
+        data_dir=provider.data_dir,
+        api_keys=api_keys_from_env(),
+    )
+    onchain_router = create_onchain_router(onchain_manager)
+
     def _on_data_update(symbol: str, base_tf: str) -> None:
         """后台刷新线程回调：广播基础及衍生周期更新给 WebSocket 订阅者。"""
         with provider._lock:
@@ -1165,9 +1178,12 @@ def create_app(provider: DataProvider) -> FastAPI:
         provider.start_background_workers()
         # 启动 WebSocket 实时监听（asyncio 后台任务）
         provider.start_watch_tasks()
+        # 启动链上指标后台刷新
+        onchain_manager.start()
         try:
             yield
         finally:
+            onchain_manager.stop()
             provider.stop()
 
     app = FastAPI(title="Chan 数据提供商", version="1.0.0", lifespan=lifespan)
@@ -1180,6 +1196,9 @@ def create_app(provider: DataProvider) -> FastAPI:
         allow_headers=["*"],
     )
 
+    # 注册链上指标 API
+    app.include_router(onchain_router)
+
     @app.get("/health")
     async def health() -> Dict[str, object]:
         """存活检查：交易所、交易对、基础/衍生周期、是否已完成冷启动。"""