Separate Alpaca price data into dedicated AlpacaPriceData table to avoid
UniqueConstraint('ticker', 'date') conflicts with Yahoo Finance PriceData.
Add Redis caching (build_cache_key/get_cached_response/set_cached_response)
to 3 Alpaca endpoints and 2 FINRA query endpoints with appropriate TTLs.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Extract shared SECHttpClient from ETF fetcher (retry, backoff, cache, throttle)
and apply it to both ETF and core SEC services, fixing missing rate limiting.
Add SECFiling DB model, Pydantic schemas, SECFilingsService with auto-indexing,
and REST endpoints at /filings/search, /filings/documents, /filings/exhibit.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>