fix: use actual symbol-specific leverage in notifications

Fixed Telegram notification showing wrong leverage (10x instead of 20x).

Problem:
- SOL trades use SOLANA_LEVERAGE=20x (per-symbol override)
- API response was returning config.leverage (global default 10x)
- n8n workflow displayed incorrect leverage value

Changes:
- Line 345: Use 'leverage' variable (from getPositionSizeForSymbol)
- Line 448: ActiveTrade uses actual leverage
- Line 522: ExecuteTradeResponse uses actual leverage
- Line 557: Database createTrade() uses actual leverage

Now notifications correctly show 20x for SOL trades.

app/api/trading/execute/route.ts

@@ -342,7 +342,7 @@ export async function POST(request: NextRequest): Promise<NextResponse<ExecuteTr
           direction: body.direction,
           entryPrice: openResult.fillPrice!,
           positionSizeUSD: positionSizeUSD,
-          leverage: config.leverage,
+          leverage: leverage, // Use actual symbol-specific leverage
           stopLossPrice: 0, // Not applicable for phantom
           takeProfit1Price: 0,
           takeProfit2Price: 0,
@@ -445,7 +445,7 @@ export async function POST(request: NextRequest): Promise<NextResponse<ExecuteTr
       entryPrice,
       entryTime: Date.now(),
       positionSize: positionSizeUSD,
-      leverage: config.leverage,
+      leverage: leverage, // Use actual symbol-specific leverage
       stopLossPrice,
       tp1Price,
       tp2Price,
@@ -519,7 +519,7 @@ export async function POST(request: NextRequest): Promise<NextResponse<ExecuteTr
       direction: body.direction,
       entryPrice: entryPrice,
       positionSize: positionSizeUSD,
-      leverage: config.leverage,
+      leverage: leverage, // Use actual symbol-specific leverage, not global config
       stopLoss: stopLossPrice,
       takeProfit1: tp1Price,
       takeProfit2: tp2Price,
@@ -554,7 +554,7 @@ export async function POST(request: NextRequest): Promise<NextResponse<ExecuteTr
         direction: body.direction,
         entryPrice,
         positionSizeUSD: positionSizeUSD,
-        leverage: config.leverage,
+        leverage: leverage, // Use actual symbol-specific leverage, not global config
         stopLossPrice,
         takeProfit1Price: tp1Price,
         takeProfit2Price: tp2Price,