Fix 3 Code Review findings on FRE-4574

- P2: Replace wget with curl for ECS health check (Alpine lacks wget)
- P2: Add AWS credentials step to CI terraform-plan job for S3 backend auth
- P3: Remove unused GitHub provider from infra/main.tf

Co-Authored-By: Paperclip <noreply@paperclip.ing>

test-ws-maxpayload.js

@@ -0,0 +1,44 @@
+const { WebSocketServer } = require('ws');
+const { createServer } = require('http');
+
+// Test WebSocket maxPayload parameter
+const httpServer = createServer();
+const wss = new WebSocketServer({
+  port: 0,
+  maxPayload: 65536, // 64KB
+});
+
+let testPassed = false;
+
+wss.on('connection', (ws) => {
+  console.log('Client connected');
+  
+  // Send message larger than 64KB
+  const oversized = 'x'.repeat(70000);
+  
+  console.log('Sending 70KB message...');
+  ws.send(oversized, (err) => {
+    if (err) {
+      console.log('✓ Error received (expected):', err.message);
+      testPassed = true;
+    } else {
+      console.log('✗ No error - maxPayload NOT enforced!');
+    }
+    
+    ws.close();
+    httpServer.close();
+    wss.close();
+    
+    if (testPassed) {
+      console.log('✅ TEST PASSED: maxPayload (64KB) is enforced');
+      process.exit(0);
+    } else {
+      console.log('❌ TEST FAILED');
+      process.exit(1);
+    }
+  });
+});
+
+httpServer.listen(0, () => {
+  console.log('Server listening on port', httpServer.address().port);
+});