Display signal quality score on analytics dashboard

- Add signalQualityScore to LastTrade interface
- Display quality score badge in last trade section (0-100)
- Color-coded: green (80+), yellow (70-79), orange (60-69)
- Shows 'Excellent', 'Good', or 'Marginal' label
- Gracefully handles null values (old trades without scores)
- Better layout when quality score is present

app/api/analytics/last-trade/route.ts

@@ -35,6 +35,7 @@ export async function GET() {
       takeProfit1Price: trade.takeProfit1Price,
       takeProfit2Price: trade.takeProfit2Price,
       isTestTrade: trade.isTestTrade || false,
+      signalQualityScore: trade.signalQualityScore || undefined,
     }
     
     return NextResponse.json({