项目目录从 refer 迁移到 local

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

local/backend/app/data_providers/__init__.py

@@ -0,0 +1,8 @@
+"""Market data provider abstraction.
+
+Providers normalize external data sources into the internal parquet schema.
+"""
+from app.data_providers.base import AssetType, MarketDataProvider, ProviderCapabilities
+from app.data_providers.registry import get_provider
+
+__all__ = ["AssetType", "MarketDataProvider", "ProviderCapabilities", "get_provider"]