FINAL FIX: Docker API URL resolution for internal service communication

- Fixed internal API calls in Docker environment to use port 3000 instead of 9000
- Added DOCKER_ENV detection to properly route internal fetch requests
- Resolves ECONNREFUSED errors when APIs try to call each other within container
- Trade validation now works correctly in Docker: 5 USD position validates properly
- Successfully tested: amountUSD field properly passed through validation pipeline
- Both development and Docker environments now fully functional

app/canvas-chart/page.tsx

@@ -0,0 +1,12 @@
+'use client'
+import React from 'react'
+import SimpleTradingChart from '../../components/SimpleTradingChart'
+
+export default function SimpleChartPage() {
+  return (
+    <div className="min-h-screen bg-gray-900 p-8">
+      <h1 className="text-white text-3xl mb-6">Simple Canvas Chart Test</h1>
+      <SimpleTradingChart symbol="SOL/USDC" positions={[]} />
+    </div>
+  )
+}