Fetch a historical time series of daily market-level snapshots (overall market sentiment, not a single ticker). Call this when the user asks how the overall market mood/regime has trended over time, wants to chart market α-sentiment / z-score over a window, or needs a range of daily market snapshots to compute averages or momentum.
Optional: `days` (1-1000, default 30; tier may cap lower). For a single ticker's history use get_ticker_history instead.
Tier caps on `days`: free=7, alpha=365, pro=730, enterprise=1000. The `date` parameter (end-date anchor) is only honored for enterprise tier — for all other tiers it is silently ignored and the window always ends at the most recent available snapshot.
Returns: array of daily market snapshots (oldest first), each with snapshot_date plus all standard MarketSnapshot fields. Response also reports tier_cap, effective_days, start_date, end_date and date_param_honored.