use node: prefix for requires

mostly because code is being autogenerated by all the AI stuff using
this prefix. it's also used in the stack trace.

src/test/dockerproxy-test.js

@@ -8,7 +8,7 @@
 'use strict';
 
 
-const child_process = require('child_process'),
+const child_process = require('node:child_process'),
     common = require('./common.js'),
     constants = require('../constants.js'),
     dockerProxy = require('../dockerproxy.js'),