fix: reconcile local positions against the live exchange book — stop lost PnL

Root cause of the dashboard under-reporting: any missed or unmatched fill
(position flip, sync gap, liquidation) left a 'zombie' OPEN row. Every later
close on that symbol landed as a partial close against the zombie, so the
row never reached CLOSED and its realized PnL never entered the closed-trade
statistics — Edge Profile, realized P/L, win rate, and the AI's own
track-record context all silently under-reported.

Fix: after each Hyperliquid order sync, reconcile local OPEN rows against the
exchange's live book (core perps + xyz dex), scoped by exchange account so
rows left by prior autopilot incarnations (each relaunch mints a fresh
trader_id sharing one exchange) are healed too. Rows the exchange no longer
holds are closed with their accumulated PnL; oversized rows are trimmed to
the live quantity. Live run confirmed: 9 zombie rows closed across
incarnations, book now matches the exchange exactly.

Also removes the header language switcher (desktop + mobile) and the
login/setup LanguageSwitcher — the product UI is English-only.

New store methods GetOpenPositionsByExchange + ReconcileOpenPositionsWithLive
with cross-incarnation test coverage.

store/position.go

@@ -347,6 +347,27 @@ func (s *PositionStore) GetOpenPositions(traderID string) ([]*TraderPosition, er
 	return positions, nil
 }
 
+// GetOpenPositionsByExchange returns every OPEN row on an exchange account,
+// across all trader IDs. An exchange account is shared by every "NOFX
+// Autopilot" relaunch (each relaunch mints a fresh trader_id), so reconciling
+// must be scoped to the exchange — not the current trader_id — or rows left by
+// prior incarnations become permanent orphans that never close.
+func (s *PositionStore) GetOpenPositionsByExchange(exchangeID string) ([]*TraderPosition, error) {
+	var positions []*TraderPosition
+	err := s.db.Where("exchange_id = ? AND status = ?", exchangeID, "OPEN").
+		Order("entry_time DESC").
+		Find(&positions).Error
+	if err != nil {
+		return nil, fmt.Errorf("failed to query open positions by exchange: %w", err)
+	}
+	for _, pos := range positions {
+		if pos.EntryQuantity == 0 {
+			pos.EntryQuantity = pos.Quantity
+		}
+	}
+	return positions, nil
+}
+
 // GetOpenPositionBySymbol gets open position for specified symbol and direction
 func (s *PositionStore) GetOpenPositionBySymbol(traderID, symbol, side string) (*TraderPosition, error) {
 	var pos TraderPosition