4501bbebd4
Two tiers of market data: 1. Per-ticker prev bars (existing 50 sources, 15-min cadence) for watchlist detail — trading decisions, stop-loss, position sizing 2. Grouped daily (new single source, once per day) for broad market context — correlation analysis, sector rotation, competitive intel Changes: - Add grouped_daily endpoint to PolygonMarketAdapter with auto date calculation (previous trading day, skip weekends) - Add fetch_global_market_sources() to scheduler for sources without company_id, scheduled once daily (86400s cadence) - Update _persist_market_items to use item-level ticker from T field and look up company_id dynamically for grouped daily bars - Migration 020: make company_id nullable on sources and market_snapshots tables, add grouped daily source row - Fix backtest replay to query market_snapshots data->>'c' for prices