feat(hyperliquid): Add Unified Account support for Spot as Perp collateral (#1387)

This PR adds support for Hyperliquid's Unified Account mode where Spot USDC
balance can be used as collateral for Perpetual trading.

Changes:
- Add HyperliquidUnifiedAcct field to Exchange config (default: true)
- Update HyperliquidTrader to support unified account mode
- When enabled, Spot USDC balance is added to available trading balance
- Update API request/response structs for unified account toggle
- Update trader config propagation from exchange config

This aligns with Hyperliquid's roadmap to make Unified Account the default.

store/exchange.go

@@ -29,6 +29,7 @@ type Exchange struct {
 	Passphrase              crypto.EncryptedString `gorm:"column:passphrase;default:''" json:"passphrase"`
 	Testnet                 bool            `gorm:"default:false" json:"testnet"`
 	HyperliquidWalletAddr   string          `gorm:"column:hyperliquid_wallet_addr;default:''" json:"hyperliquidWalletAddr"`
+	HyperliquidUnifiedAcct  bool            `gorm:"column:hyperliquid_unified_account;default:true" json:"hyperliquidUnifiedAccount"` // Unified Account mode (Spot as collateral)
 	AsterUser               string          `gorm:"column:aster_user;default:''" json:"asterUser"`
 	AsterSigner             string          `gorm:"column:aster_signer;default:''" json:"asterSigner"`
 	AsterPrivateKey         crypto.EncryptedString `gorm:"column:aster_private_key;default:''" json:"asterPrivateKey"`
@@ -181,7 +182,8 @@ func getExchangeNameAndType(exchangeType string) (name string, typ string) {
 // Create creates a new exchange account with UUID
 func (s *ExchangeStore) Create(userID, exchangeType, accountName string, enabled bool,
 	apiKey, secretKey, passphrase string, testnet bool,
-	hyperliquidWalletAddr, asterUser, asterSigner, asterPrivateKey,
+	hyperliquidWalletAddr string, hyperliquidUnifiedAcct bool,
+	asterUser, asterSigner, asterPrivateKey,
 	lighterWalletAddr, lighterPrivateKey, lighterApiKeyPrivateKey string, lighterApiKeyIndex int) (string, error) {
 
 	id := uuid.New().String()
@@ -207,6 +209,7 @@ func (s *ExchangeStore) Create(userID, exchangeType, accountName string, enabled
 		Passphrase:              crypto.EncryptedString(passphrase),
 		Testnet:                 testnet,
 		HyperliquidWalletAddr:   hyperliquidWalletAddr,
+		HyperliquidUnifiedAcct:  hyperliquidUnifiedAcct,
 		AsterUser:               asterUser,
 		AsterSigner:             asterSigner,
 		AsterPrivateKey:         crypto.EncryptedString(asterPrivateKey),
@@ -224,15 +227,17 @@ func (s *ExchangeStore) Create(userID, exchangeType, accountName string, enabled
 
 // Update updates exchange configuration by UUID
 func (s *ExchangeStore) Update(userID, id string, enabled bool, apiKey, secretKey, passphrase string, testnet bool,
-	hyperliquidWalletAddr, asterUser, asterSigner, asterPrivateKey, lighterWalletAddr, lighterPrivateKey, lighterApiKeyPrivateKey string, lighterApiKeyIndex int) error {
+	hyperliquidWalletAddr string, hyperliquidUnifiedAcct bool,
+	asterUser, asterSigner, asterPrivateKey, lighterWalletAddr, lighterPrivateKey, lighterApiKeyPrivateKey string, lighterApiKeyIndex int) error {
 
 	logger.Debugf("🔧 ExchangeStore.Update: userID=%s, id=%s, enabled=%v", userID, id, enabled)
 
 	updates := map[string]interface{}{
-		"enabled":                 enabled,
-		"testnet":                 testnet,
-		"hyperliquid_wallet_addr": hyperliquidWalletAddr,
-		"aster_user":              asterUser,
+		"enabled":                       enabled,
+		"testnet":                       testnet,
+		"hyperliquid_wallet_addr":       hyperliquidWalletAddr,
+		"hyperliquid_unified_account":   hyperliquidUnifiedAcct,
+		"aster_user":                    asterUser,
 		"aster_signer":            asterSigner,
 		"lighter_wallet_addr":     lighterWalletAddr,
 		"lighter_api_key_index":   lighterApiKeyIndex,
@@ -307,7 +312,8 @@ func (s *ExchangeStore) CreateLegacy(userID, id, name, typ string, enabled bool,
 	// Check if this is an old-style ID (exchange type as ID)
 	if id == "binance" || id == "bybit" || id == "okx" || id == "bitget" || id == "hyperliquid" || id == "aster" || id == "lighter" {
 		_, err := s.Create(userID, id, "Default", enabled, apiKey, secretKey, "", testnet,
-			hyperliquidWalletAddr, asterUser, asterSigner, asterPrivateKey, "", "", "", 0)
+			hyperliquidWalletAddr, true, // Default to Unified Account mode
+			asterUser, asterSigner, asterPrivateKey, "", "", "", 0)
 		return err
 	}