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/mail.js

@@ -59,7 +59,7 @@ exports = module.exports = {
     _updateDomain: updateDomain
 };
 
-const assert = require('assert'),
+const assert = require('node:assert'),
     BoxError = require('./boxerror.js'),
     constants = require('./constants.js'),
     database = require('./database.js'),
@@ -70,11 +70,11 @@ const assert = require('assert'),
     mailer = require('./mailer.js'),
     mailServer = require('./mailserver.js'),
     mysql = require('mysql2'),
-    net = require('net'),
+    net = require('node:net'),
     network = require('./network.js'),
     nodemailer = require('nodemailer'),
     notifications = require('./notifications.js'),
-    path = require('path'),
+    path = require('node:path'),
     platform = require('./platform.js'),
     safe = require('safetydance'),
     services = require('./services.js'),