Take-Profit, Stop-Loss & Trailing Stop per Asset Class
TP/SL: % of position value (notional). Stop-Loss should be ≥ 2× spread. MIN_SPREAD_MULT = 3× (fixed in code).
Trailing Stop: % of peak profit allowed to give back before closing. 0 = disabled. Example: 40 → exit when P&L drops below 60% of peak. Activated at 0.5% of position value as peak.