fix(dashboard): current spread sign for HL→BG positions

Bug: current spread always computed as (hl-bg)/bg regardless of
position direction. For HL→BG positions, spread should be (bg-hl)/hl
to match entry spread convention.

Fix: check LongLeg.Exchange — if HL→BG, use (bg-hl)/hl instead.

dashboard.go

@@ -323,6 +323,10 @@ func (d *Dashboard) broadcastLoop() {
 					netPnl := longPnl + shortPnl - totalFees
 
 					currentSpread := (hlP - bgP) / bgP * 100
+					if pos.LongLeg.Exchange == ExHyperLiquid {
+						// HL→BG: spread positive when bgP > hlP
+						currentSpread = (bgP - hlP) / hlP * 100
+					}
 					posEntry["current_spread"] = math.Round(currentSpread*10000) / 10000
 					posEntry["pnl_est"] = math.Round(netPnl*10000) / 10000
 				}