feat(exchange): add Bybit Futures support (#1100)

* feat(exchange): add Bybit Futures support

- Add Bybit Go SDK dependency (github.com/bybit-exchange/bybit.go.api)
- Create trader/bybit_trader.go implementing Trader interface for USDT perpetual futures
- Update config/database.go to include Bybit in default exchanges
- Update manager/trader_manager.go to handle Bybit API key configuration
- Update trader/auto_trader.go to add BybitAPIKey/BybitSecretKey fields and bybit case
- Add Bybit icon to frontend ExchangeIcons.tsx

Bybit uses standard API Key/Secret Key authentication (similar to Binance).
Only USDT perpetual futures (category=linear) are supported.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: tinkle-community <tinklefund@gmail.com>

* test(bybit): add comprehensive unit tests for Bybit trader

- Add BybitTraderTestSuite following existing test patterns
- Interface compliance test (Trader interface)
- Symbol format validation tests
- FormatQuantity tests with 3-decimal precision
- API response parsing tests (success, error, permission denied)
- Position side conversion tests (Buy->long, Sell->short)
- Cache duration verification test
- Mock server integration tests for API endpoints

All 12 Bybit tests pass.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: tinkle-community <tinklefund@gmail.com>

* fix(frontend): add Bybit support to exchange config forms

修復前端對 Bybit 交易所的支持：
- 添加 Bybit 到 API Key/Secret Key 輸入欄位顯示邏輯
- 添加 Bybit 的表單驗證邏輯
- 修復 ExchangeConfigModal.tsx 和 AITradersPage.tsx

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: tinkle-community <tinklefund@gmail.com>

---------

Co-authored-by: the-dev-z <the-dev-z@users.noreply.github.com>
Co-authored-by: tinkle-community <tinklefund@gmail.com>

trader/auto_trader.go

@@ -23,12 +23,16 @@ type AutoTraderConfig struct {
 	AIModel string // AI模型: "qwen" 或 "deepseek"
 
 	// 交易平台选择
-	Exchange string // "binance", "hyperliquid", "aster" 或 "lighter"
+	Exchange string // "binance", "bybit", "hyperliquid", "aster" 或 "lighter"
 
 	// 币安API配置
 	BinanceAPIKey    string
 	BinanceSecretKey string
 
+	// Bybit API配置
+	BybitAPIKey    string
+	BybitSecretKey string
+
 	// Hyperliquid配置
 	HyperliquidPrivateKey string
 	HyperliquidWalletAddr string
@@ -184,6 +188,9 @@ func NewAutoTrader(config AutoTraderConfig, database interface{}, userID string)
 	case "binance":
 		log.Printf("🏦 [%s] 使用币安合约交易", config.Name)
 		trader = NewFuturesTrader(config.BinanceAPIKey, config.BinanceSecretKey, userID)
+	case "bybit":
+		log.Printf("🏦 [%s] 使用Bybit合约交易", config.Name)
+		trader = NewBybitTrader(config.BybitAPIKey, config.BybitSecretKey)
 	case "hyperliquid":
 		log.Printf("🏦 [%s] 使用Hyperliquid交易", config.Name)
 		trader, err = NewHyperliquidTrader(config.HyperliquidPrivateKey, config.HyperliquidWalletAddr, config.HyperliquidTestnet)