The VaR engine's get_symbol_volatility used hardcoded per-asset-class
annual volatility values (e.g. 25% for equities, 80% for crypto) without
any indication to operators that real market data was not being used.
Now emits a tracing::warn on every static volatility lookup so operators
see it in logs. Also adds a volatility_overrides HashMap<String, f64>
field on VarEngine for manual per-symbol overrides until a real market
data feed is integrated.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>