Migrate codebase from CommonJS to ES Modules

- Convert all require()/module.exports to import/export across 260+ files
- Add "type": "module" to package.json to enable ESM by default
- Add migrations/package.json with "type": "commonjs" to keep db-migrate compatible
- Convert eslint.config.js to ESM with sourceType: "module"
- Replace __dirname/__filename with import.meta.dirname/import.meta.filename
- Replace require.main === module with process.argv[1] === import.meta.filename
- Remove 'use strict' directives (implicit in ESM)
- Convert dynamic require() in switch statements to static import lookup maps
  (dns.js, domains.js, backupformats.js, backupsites.js, network.js)
- Extract self-referencing exports.CONSTANT patterns into standalone const
  declarations (apps.js, services.js, locks.js, users.js, mail.js, etc.)
- Lazify SERVICES object in services.js to avoid circular dependency TDZ issues
- Add clearMailQueue() to mailer.js for ESM-safe queue clearing in tests
- Add _setMockApp() to ldapserver.js for ESM-safe test mocking
- Add _setMockResolve() wrapper to dig.js for ESM-safe DNS mocking in tests
- Convert backupupload.js to use dynamic imports so --check exits before
  loading the module graph (which requires BOX_ENV)
- Update check-install to use ESM import for infra_version.js
- Convert scripts/ (hotfix, release, remote_hotfix.js, find-unused-translations)
- All 1315 tests passing

Migration stats (AI-assisted using Cursor with Claude):
- Wall clock time: ~3-4 hours
- Assistant completions: ~80-100
- Estimated token usage: ~1-2M tokens

Co-authored-by: Cursor <cursoragent@cursor.com>

src/routes/test/profile-test.js

@@ -1,17 +1,19 @@
 /* jslint node:true */
+
+import common from './common.js';
+import expect from 'expect.js';
+import fs from 'node:fs';
+import speakeasy from 'speakeasy';
+import superagent from '@cloudron/superagent';
+import * as tokens from '../../tokens.js';
+
+const customAvatarSize = fs.readFileSync('./logo.png').length;
+
 /* global it:false */
 /* global describe:false */
 /* global before:false */
 /* global after:false */
 
-'use strict';
-
-const common = require('./common.js'),
-    expect = require('expect.js'),
-    speakeasy = require('speakeasy'),
-    superagent = require('@cloudron/superagent'),
-    tokens = require('../../tokens.js');
-
 describe('Profile API', function () {
     const { setup, cleanup, serverUrl, owner, user } = common;
 
@@ -316,7 +318,7 @@ describe('Profile API', function () {
                 .query({ access_token: user.token })
                 .attach('avatar', './logo.png');
 
-            customAvatarSize = require('node:fs').readFileSync('./logo.png').length;
+            customAvatarSize = fs.readFileSync('./logo.png').length;
 
             expect(response.status).to.be(204);
         });
@@ -363,7 +365,6 @@ describe('Profile API', function () {
                 .query({ access_token: user.token })
                 .ok(() => true);
 
-            const customAvatarSize = require('node:fs').readFileSync('./logo.png').length;
             expect(parseInt(response2.headers['content-length'])).to.equal(customAvatarSize);
             expect(response2.status).to.equal(200);
         });