Module `Algostream_risk_management.Drawdown`

Streaming drawdown tracker.

Online complement to Algostream_domain_portfolio.Portfolio.Risk_metrics.calculate_maximum_drawdown (which computes max-DD offline over a NAV history). Tracker.update consumes one equity point at a time and maintains running peak / current DD / max DD / time under water.

Out-of-order updates (older ts_ns) are silently ignored — we don't rewind.

module Tracker : sig ... end