Fix nil pointer in algeneva NewConnectionEx error path

The conn variable was shadowed by the return from newConnectionEx,
causing CloseOnHandshakeFailure to receive nil when the handshake
fails (e.g., port readiness check sends empty data).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: myleshorton

protocol/algeneva/inbound.go

@@ -69,13 +69,13 @@ func (a *Inbound) Close() error {
 func (a *Inbound) NewConnectionEx(ctx context.Context, conn net.Conn, metadata adapter.InboundContext, onClose N.CloseHandlerFunc) {
 	metadata.Inbound = a.Tag()
 	metadata.InboundType = a.Type()
-	conn, err := a.newConnectionEx(ctx, conn)
+	wsConn, err := a.newConnectionEx(ctx, conn)
 	if err != nil {
 		N.CloseOnHandshakeFailure(conn, onClose, err)
 		a.logger.ErrorContext(ctx, exceptions.Cause(err, "process connection from ", metadata.Source))
 		return
 	}
-	a.httpInbound.NewConnectionEx(ctx, conn, metadata, onClose)
+	a.httpInbound.NewConnectionEx(ctx, wsConn, metadata, onClose)
 }
 
 // newConnectionEx processes the connection and upgrades it to a WebSocket connection.