feat: Add phantom trade detection and database tracking

- Detect position size mismatches (>50% variance) after opening
- Save phantom trades to database with expectedSizeUSD, actualSizeUSD, phantomReason
- Return error from execute endpoint to prevent Position Manager tracking
- Add comprehensive documentation of phantom trade issue and solution
- Enable data collection for pattern analysis and future optimization

Fixes oracle price lag issue during volatile markets where transactions
confirm but positions don't actually open at expected size.

app/api/trading/execute/route.ts

@@ -372,6 +372,68 @@ export async function POST(request: NextRequest): Promise<NextResponse<ExecuteTr
         { status: 500 }
       )
     }
+    
+    // CRITICAL: Check for phantom trade (position opened but size mismatch)
+    if (openResult.isPhantom) {
+      console.error(`🚨 PHANTOM TRADE DETECTED - Not adding to Position Manager`)
+      console.error(`   Expected: $${positionSizeUSD.toFixed(2)}`)
+      console.error(`   Actual: $${openResult.actualSizeUSD?.toFixed(2)}`)
+      
+      // Save phantom trade to database for analysis
+      try {
+        const qualityScore = calculateQualityScore({
+          atr: body.atr,
+          adx: body.adx,
+          rsi: body.rsi,
+          volumeRatio: body.volumeRatio,
+          pricePosition: body.pricePosition,
+          direction: body.direction,
+        })
+        
+        await createTrade({
+          positionId: openResult.transactionSignature!,
+          symbol: driftSymbol,
+          direction: body.direction,
+          entryPrice: openResult.fillPrice!,
+          positionSizeUSD: positionSizeUSD,
+          leverage: config.leverage,
+          stopLossPrice: 0, // Not applicable for phantom
+          takeProfit1Price: 0,
+          takeProfit2Price: 0,
+          tp1SizePercent: 0,
+          tp2SizePercent: 0,
+          configSnapshot: config,
+          entryOrderTx: openResult.transactionSignature!,
+          signalStrength: body.signalStrength,
+          timeframe: body.timeframe,
+          atrAtEntry: body.atr,
+          adxAtEntry: body.adx,
+          rsiAtEntry: body.rsi,
+          volumeAtEntry: body.volumeRatio,
+          pricePositionAtEntry: body.pricePosition,
+          signalQualityScore: qualityScore,
+          // Phantom-specific fields
+          status: 'phantom',
+          isPhantom: true,
+          expectedSizeUSD: positionSizeUSD,
+          actualSizeUSD: openResult.actualSizeUSD,
+          phantomReason: 'ORACLE_PRICE_MISMATCH', // Likely cause based on logs
+        })
+        
+        console.log(`💾 Phantom trade saved to database for analysis`)
+      } catch (dbError) {
+        console.error('❌ Failed to save phantom trade:', dbError)
+      }
+      
+      return NextResponse.json(
+        {
+          success: false,
+          error: 'Phantom trade detected',
+          message: `Position opened but size mismatch detected. Expected $${positionSizeUSD.toFixed(2)}, got $${openResult.actualSizeUSD?.toFixed(2)}. This usually indicates oracle price was stale or order was rejected by exchange.`,
+        },
+        { status: 500 }
+      )
+    }
 
     // Calculate stop loss and take profit prices
     const entryPrice = openResult.fillPrice!