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/scheduler.js

@@ -9,7 +9,7 @@ exports = module.exports = {
 };
 
 const apps = require('./apps.js'),
-    assert = require('assert'),
+    assert = require('node:assert'),
     BoxError = require('./boxerror.js'),
     cloudron = require('./cloudron.js'),
     constants = require('./constants.js'),