feat: enhance backtest with real-time positions, P&L fixes, and strategy integration

- Add real-time position display with unrealized P&L during backtest
- Fix P&L calculation by tracking accumulated opening fees
- Add strategy coin source resolution (AI500, OI Top, mixed)
- Infer AI provider from model name for better compatibility
- Cap position size to available margin to prevent insufficient cash errors
- Fix trade markers on K-line chart (long/short instead of buy/sell)
- Add QuantData and OI ranking to backtest decision context

backtest/config.go

@@ -29,6 +29,7 @@ type BacktestConfig struct {
 	RunID                string   `json:"run_id"`
 	UserID               string   `json:"user_id,omitempty"`
 	AIModelID            string   `json:"ai_model_id,omitempty"`
+	StrategyID           string   `json:"strategy_id,omitempty"` // Optional: use saved strategy from Strategy Studio
 	Symbols              []string `json:"symbols"`
 	Timeframes           []string `json:"timeframes"`
 	DecisionTimeframe    string   `json:"decision_timeframe"`
@@ -53,6 +54,9 @@ type BacktestConfig struct {
 	CheckpointIntervalBars    int    `json:"checkpoint_interval_bars,omitempty"`
 	CheckpointIntervalSeconds int    `json:"checkpoint_interval_seconds,omitempty"`
 	ReplayDecisionDir         string `json:"replay_decision_dir,omitempty"`
+
+	// Internal: loaded strategy config (set by Manager when StrategyID is provided)
+	loadedStrategy *store.StrategyConfig `json:"-"`
 }
 
 // Validate performs validity checks on the configuration and fills in default values.
@@ -178,10 +182,54 @@ func validateFillPolicy(policy string) error {
 	}
 }
 
+// SetLoadedStrategy sets the loaded strategy config from database.
+func (cfg *BacktestConfig) SetLoadedStrategy(strategy *store.StrategyConfig) {
+	cfg.loadedStrategy = strategy
+}
+
 // ToStrategyConfig converts BacktestConfig to StrategyConfig for unified prompt generation.
 // This ensures backtest uses the same StrategyEngine logic as live trading.
+// If a strategy was loaded from database (via StrategyID), it will be used with overrides.
 func (cfg *BacktestConfig) ToStrategyConfig() *store.StrategyConfig {
-	// Determine primary and longer timeframe from the timeframes list
+	// If a strategy was loaded from database, use it with some overrides
+	if cfg.loadedStrategy != nil {
+		result := *cfg.loadedStrategy // Make a copy
+
+		// Override coin source with backtest symbols (回测指定的币对优先)
+		if len(cfg.Symbols) > 0 {
+			result.CoinSource.SourceType = "static"
+			result.CoinSource.StaticCoins = cfg.Symbols
+			result.CoinSource.UseCoinPool = false
+			result.CoinSource.UseOITop = false
+		}
+
+		// Override timeframes with backtest config
+		if len(cfg.Timeframes) > 0 {
+			result.Indicators.Klines.SelectedTimeframes = cfg.Timeframes
+			result.Indicators.Klines.PrimaryTimeframe = cfg.Timeframes[0]
+			if len(cfg.Timeframes) > 1 {
+				result.Indicators.Klines.LongerTimeframe = cfg.Timeframes[len(cfg.Timeframes)-1]
+			}
+			result.Indicators.Klines.EnableMultiTimeframe = len(cfg.Timeframes) > 1
+		}
+
+		// Override leverage with backtest config
+		if cfg.Leverage.BTCETHLeverage > 0 {
+			result.RiskControl.BTCETHMaxLeverage = cfg.Leverage.BTCETHLeverage
+		}
+		if cfg.Leverage.AltcoinLeverage > 0 {
+			result.RiskControl.AltcoinMaxLeverage = cfg.Leverage.AltcoinLeverage
+		}
+
+		// Override custom prompt if provided in backtest config
+		if cfg.CustomPrompt != "" {
+			result.CustomPrompt = cfg.CustomPrompt
+		}
+
+		return &result
+	}
+
+	// Fallback: build strategy config from backtest config (original logic)
 	primaryTF := "5m"
 	longerTF := "4h"
 	if len(cfg.Timeframes) > 0 {