feat(gate): complete Gate.io exchange integration with trader refactoring

Gate.io Integration:
- Add Gate trader with full Trader interface implementation
- Add order_sync.go for background trade synchronization
- Fix quantity display (convert contracts to actual tokens via quanto_multiplier)
- Fix fill price return in OpenLong/OpenShort/CloseLong/CloseShort
- Add Gate-specific CoinAnk K-line data source support
- Add Gate to supported exchanges in frontend and backend
- Add Gate/KuCoin logo SVG icons

Trader Package Refactoring:
- Move exchange-specific code into subdirectories (binance/, bybit/, okx/, bitget/, hyperliquid/, aster/, lighter/, gate/)
- Create types/ package for shared types to avoid circular dependencies
- Move TraderTestSuite to trader/testutil package to avoid import cycles
- Update market.GetWithExchange to support exchange-specific data

trader/lighter/order_sync.go

@@ -0,0 +1,161 @@
+package lighter
+
+import (
+	"fmt"
+	"nofx/logger"
+	"nofx/market"
+	"nofx/store"
+	"sort"
+	"strings"
+	"time"
+)
+
+// SyncOrdersFromLighter syncs Lighter exchange trade history to local database
+// Also creates/updates position records to ensure orders/fills/positions data consistency
+// exchangeID: Exchange account UUID (from exchanges.id)
+// exchangeType: Exchange type ("lighter")
+func (t *LighterTraderV2) SyncOrdersFromLighter(traderID string, exchangeID string, exchangeType string, st *store.Store) error {
+	if st == nil {
+		return fmt.Errorf("store is nil")
+	}
+
+	// Get recent trades (last 24 hours)
+	startTime := time.Now().Add(-24 * time.Hour)
+
+	logger.Infof("🔄 Syncing Lighter trades from: %s", startTime.Format(time.RFC3339))
+
+	// Use GetTrades method to fetch trade records (same as other exchanges)
+	trades, err := t.GetTrades(startTime, 100)
+	if err != nil {
+		return fmt.Errorf("failed to get trades: %w", err)
+	}
+
+	logger.Infof("📥 Received %d trades from Lighter", len(trades))
+
+	// Sort trades by time ASC (oldest first) for proper position building
+	sort.Slice(trades, func(i, j int) bool {
+		return trades[i].Time.UnixMilli() < trades[j].Time.UnixMilli()
+	})
+
+	// Process trades one by one (no transaction to avoid deadlock)
+	orderStore := st.Order()
+	positionStore := st.Position()
+	posBuilder := store.NewPositionBuilder(positionStore)
+
+	syncedCount := 0
+	for _, trade := range trades {
+		// Check if trade already exists (use exchangeID which is UUID, not exchange type)
+		existing, err := orderStore.GetOrderByExchangeID(exchangeID, trade.TradeID)
+		if err == nil && existing != nil {
+			continue // Trade already exists, skip
+		}
+
+		// Normalize symbol (add USDT suffix)
+		symbol := market.Normalize(trade.Symbol)
+
+		// Use OrderAction from TradeRecord (determined by position change in GetTrades)
+		// This is more accurate than guessing based on database state
+		positionSide := trade.PositionSide
+		orderAction := trade.OrderAction
+		side := trade.Side
+
+		// Fallback if OrderAction is empty (shouldn't happen with updated GetTrades)
+		if orderAction == "" {
+			if strings.ToUpper(side) == "BUY" {
+				positionSide = "LONG"
+				orderAction = "open_long"
+			} else {
+				positionSide = "SHORT"
+				orderAction = "open_short"
+			}
+		}
+
+		// Create order record - use Unix milliseconds UTC
+		tradeTimeMs := trade.Time.UTC().UnixMilli()
+		orderRecord := &store.TraderOrder{
+			TraderID:        traderID,
+			ExchangeID:      exchangeID,   // UUID
+			ExchangeType:    exchangeType, // Exchange type
+			ExchangeOrderID: trade.TradeID,
+			Symbol:          symbol,
+			Side:            strings.ToUpper(side),
+			PositionSide:    positionSide,
+			Type:            "MARKET",
+			OrderAction:     orderAction,
+			Quantity:        trade.Quantity,
+			Price:           trade.Price,
+			Status:          "FILLED",
+			FilledQuantity:  trade.Quantity,
+			AvgFillPrice:    trade.Price,
+			Commission:      trade.Fee,
+			FilledAt:        tradeTimeMs,
+			CreatedAt:       tradeTimeMs,
+			UpdatedAt:       tradeTimeMs,
+		}
+
+		// Insert order record
+		if err := orderStore.CreateOrder(orderRecord); err != nil {
+			logger.Infof("  ⚠️ Failed to sync trade %s: %v", trade.TradeID, err)
+			continue
+		}
+
+		// Create fill record - use Unix milliseconds UTC
+		fillRecord := &store.TraderFill{
+			TraderID:        traderID,
+			ExchangeID:      exchangeID,   // UUID
+			ExchangeType:    exchangeType, // Exchange type
+			OrderID:         orderRecord.ID,
+			ExchangeOrderID: trade.TradeID,
+			ExchangeTradeID: trade.TradeID,
+			Symbol:          symbol,
+			Side:            strings.ToUpper(side),
+			Price:           trade.Price,
+			Quantity:        trade.Quantity,
+			QuoteQuantity:   trade.Price * trade.Quantity,
+			Commission:      trade.Fee,
+			CommissionAsset: "USDT",
+			RealizedPnL:     trade.RealizedPnL,
+			IsMaker:         false,
+			CreatedAt:       tradeTimeMs,
+		}
+
+		if err := orderStore.CreateFill(fillRecord); err != nil {
+			logger.Infof("  ⚠️ Failed to sync fill for trade %s: %v", trade.TradeID, err)
+		}
+
+		// Create/update position record using PositionBuilder
+		if err := posBuilder.ProcessTrade(
+			traderID, exchangeID, exchangeType,
+			symbol, positionSide, orderAction,
+			trade.Quantity, trade.Price, trade.Fee, trade.RealizedPnL,
+			tradeTimeMs, trade.TradeID,
+		); err != nil {
+			logger.Infof("  ⚠️ Failed to sync position for trade %s: %v", trade.TradeID, err)
+		} else {
+			logger.Infof("  📍 Position updated for trade: %s (action: %s, qty: %.6f)", trade.TradeID, orderAction, trade.Quantity)
+		}
+
+		syncedCount++
+		logger.Infof("  ✅ Synced trade: %s %s %s qty=%.6f price=%.6f pnl=%.2f fee=%.6f action=%s",
+			trade.TradeID, symbol, side, trade.Quantity, trade.Price, trade.RealizedPnL, trade.Fee, orderAction)
+	}
+
+	logger.Infof("✅ Order sync completed: %d new trades synced", syncedCount)
+	return nil
+}
+
+// StartOrderSync starts background order sync task
+func (t *LighterTraderV2) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration) {
+	ticker := time.NewTicker(interval)
+	go func() {
+		for range ticker.C {
+			if err := t.SyncOrdersFromLighter(traderID, exchangeID, exchangeType, st); err != nil {
+				// Only log non-404 errors to reduce log spam
+				if !strings.Contains(err.Error(), "status 404") {
+					logger.Infof("⚠️  Order sync failed: %v", err)
+				}
+			}
+		}
+	}()
+	logger.Infof("🔄 Lighter order+position sync started (interval: %v)", interval)
+}