Persist settle_index_px and surface formula in trade detail so expiry closes are not mistaken for book fills.
Co-authored-by: Cursor <cursoragent@cursor.com>
Document and enforce: A full dual-leg close, B perp-only when deep OTM with residual archive that does not block next open, and expiry settlement when target is missed.
Co-authored-by: Cursor <cursoragent@cursor.com>