feat: fix Lighter V2 integration and improve error handling

- Fix Lighter API field name mismatches (position/size, avg_entry_price/entry_price, sign/side)
- Fix GetBalance return format to match standard fields (totalWalletBalance, totalUnrealizedProfit)
- Fix GetPositions return format to match standard fields (positionAmt, markPrice, unRealizedProfit)
- Add API Key Index field to frontend with explanation
- Update Lighter referral link
- Disable Lighter testnet (mainnet only)
- Add load error tracking for better error messages
- Remove old Lighter V1 implementation files
- Remove test credentials from test files

trader/lighter_types.go

@@ -0,0 +1,81 @@
+package trader
+
+import "fmt"
+
+// AccountBalance Account balance information (Lighter)
+type AccountBalance struct {
+	TotalEquity       float64 `json:"total_equity"`       // Total equity
+	AvailableBalance  float64 `json:"available_balance"`  // Available balance
+	MarginUsed        float64 `json:"margin_used"`        // Used margin
+	UnrealizedPnL     float64 `json:"unrealized_pnl"`     // Unrealized PnL
+	MaintenanceMargin float64 `json:"maintenance_margin"` // Maintenance margin
+}
+
+// Position Position information (Lighter)
+type Position struct {
+	Symbol           string  `json:"symbol"`            // Trading pair
+	Side             string  `json:"side"`              // "long" or "short"
+	Size             float64 `json:"size"`              // Position size
+	EntryPrice       float64 `json:"entry_price"`       // Average entry price
+	MarkPrice        float64 `json:"mark_price"`        // Mark price
+	LiquidationPrice float64 `json:"liquidation_price"` // Liquidation price
+	UnrealizedPnL    float64 `json:"unrealized_pnl"`    // Unrealized PnL
+	Leverage         float64 `json:"leverage"`          // Leverage multiplier
+	MarginUsed       float64 `json:"margin_used"`       // Used margin
+}
+
+// CreateOrderRequest Create order request (Lighter)
+type CreateOrderRequest struct {
+	Symbol      string  `json:"symbol"`        // Trading pair
+	Side        string  `json:"side"`          // "buy" or "sell"
+	OrderType   string  `json:"order_type"`    // "market" or "limit"
+	Quantity    float64 `json:"quantity"`      // Quantity
+	Price       float64 `json:"price"`         // Price (required for limit orders)
+	ReduceOnly  bool    `json:"reduce_only"`   // Reduce-only flag
+	TimeInForce string  `json:"time_in_force"` // "GTC", "IOC", "FOK"
+	PostOnly    bool    `json:"post_only"`     // Post-only (maker only)
+}
+
+// OrderResponse Order response (Lighter)
+type OrderResponse struct {
+	OrderID      string  `json:"order_id"`
+	Symbol       string  `json:"symbol"`
+	Side         string  `json:"side"`
+	OrderType    string  `json:"order_type"`
+	Quantity     float64 `json:"quantity"`
+	Price        float64 `json:"price"`
+	Status       string  `json:"status"` // "open", "filled", "cancelled"
+	FilledQty    float64 `json:"filled_qty"`
+	RemainingQty float64 `json:"remaining_qty"`
+	CreateTime   int64   `json:"create_time"`
+}
+
+// LighterTradeResponse represents the response from Lighter trades API
+type LighterTradeResponse struct {
+	Trades []LighterTrade `json:"trades"`
+}
+
+// LighterTrade represents a single trade from Lighter
+type LighterTrade struct {
+	TradeID      string `json:"trade_id"`
+	AccountIndex int64  `json:"account_index"`
+	MarketIndex  int    `json:"market_index"`
+	Symbol       string `json:"symbol"`
+	Side         string `json:"side"` // "buy" or "sell"
+	Price        string `json:"price"`
+	Size         string `json:"size"`
+	RealizedPnl  string `json:"realized_pnl"`
+	Fee          string `json:"fee"`
+	Timestamp    int64  `json:"timestamp"`
+	IsMaker      bool   `json:"is_maker"`
+}
+
+// parseFloat parses a string to float64, returns 0 for empty string
+func parseFloat(s string) (float64, error) {
+	if s == "" {
+		return 0, nil
+	}
+	var f float64
+	_, err := fmt.Sscanf(s, "%f", &f)
+	return f, err
+}