Fix spot trade logic: remove incorrect positions and enhance trade history display

- Remove incorrect open positions for spot swaps (instant settlements)
- Add DELETE API route for position removal (/api/trading/positions/[positionId])
- Update existing SOL/USDC trade to clearly mark as SPOT_SWAP
- Enhance TradesHistoryPanel with visual trade type indicators:
  * SPOT_SWAP: Purple badge with ⚡ icon
  * MARKET: Blue badge with 📈 icon
  * LIMIT: Orange badge with 🎯 icon
  * STOP: Red badge with 🛑 icon
- Add trade history update functionality for modifying existing trades
- Fix container communication URLs in execute-dex route

Result: Spot trades no longer create open positions, trade history clearly shows trade types

components/TradesHistoryPanel.js

@@ -43,6 +43,21 @@ export default function TradesHistoryPanel() {
     }
   }
 
+  const getTradeTypeInfo = (trade) => {
+    switch (trade.type) {
+      case 'SPOT_SWAP':
+        return { label: 'SPOT SWAP', color: 'bg-purple-600', icon: '⚡' }
+      case 'market':
+        return { label: 'MARKET', color: 'bg-blue-600', icon: '📈' }
+      case 'limit':
+        return { label: 'LIMIT', color: 'bg-orange-600', icon: '🎯' }
+      case 'stop':
+        return { label: 'STOP', color: 'bg-red-600', icon: '🛑' }
+      default:
+        return { label: trade.type?.toUpperCase() || 'TRADE', color: 'bg-gray-600', icon: '💱' }
+    }
+  }
+
   const getSideColor = (side) => {
     return side === 'BUY' ? 'text-green-400' : 'text-red-400'
   }
@@ -122,7 +137,15 @@ export default function TradesHistoryPanel() {
                   }`}>
                     {trade.side}
                   </span>
-                  <span className="px-2 py-1 rounded text-xs bg-blue-600 text-white">
+                  {(() => {
+                    const typeInfo = getTradeTypeInfo(trade)
+                    return (
+                      <span className={`px-2 py-1 rounded text-xs font-medium text-white ${typeInfo.color}`}>
+                        {typeInfo.icon} {typeInfo.label}
+                      </span>
+                    )
+                  })()}
+                  <span className="px-2 py-1 rounded text-xs bg-gray-700 text-gray-300">
                     {trade.dex}
                   </span>
                 </div>