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/apptask.js

@@ -13,7 +13,7 @@ exports = module.exports = {
 
 const apps = require('./apps.js'),
     appstore = require('./appstore.js'),
-    assert = require('assert'),
+    assert = require('node:assert'),
     AuditSource = require('./auditsource.js'),
     backupTargets = require('./backuptargets.js'),
     backuptask = require('./backuptask.js'),
@@ -24,11 +24,11 @@ const apps = require('./apps.js'),
     dns = require('./dns.js'),
     docker = require('./docker.js'),
     ejs = require('ejs'),
-    fs = require('fs'),
+    fs = require('node:fs'),
     iputils = require('./iputils.js'),
     manifestFormat = require('@cloudron/manifest-format'),
-    os = require('os'),
-    path = require('path'),
+    os = require('node:os'),
+    path = require('node:path'),
     paths = require('./paths.js'),
     promiseRetry = require('./promise-retry.js'),
     reverseProxy = require('./reverseproxy.js'),