Module volatility 

Realized volatility for IV/RV entry gates (credit-spread edge filter).

Functions

fetch_realized_vol_pct

Fetch daily closes and compute annualized realized vol for symbol.

iv_rv_ratio

IV / RV ratio when both are positive; None if either side is missing.

realized_vol_annualized_pct

Annualized realized vol (%) from daily closes — same formula as schwab-trader regime.