[grade=A] DC-068: Fix all 3 ESLint errors + auto-fix warnings

- Removed orphaned __trace2.js (unnecessary escape error)
- Fixed empty block statement in config-migrations.test.js busy-wait
- Fixed empty block statement in metrics.test.js busy-wait
- Auto-fixed 5 fixable warnings via eslint --fix
- Remaining 547 warnings (require-await, no-unused-vars) are non-blocking code quality
- 0 errors, 1633 tests pass

dashcaddy-api/routes/auth/admin.js

@@ -241,7 +241,7 @@ module.exports = function({ asyncHandler, errorResponse, log, session, dataDir }
     if (!issued.ok) throw new ValidationError(issued.reason, 'email');
 
     let deliveredVia = 'none';
-    let maskedEmail = email.replace(/(^.).+(@.*$)/, '$1***$2');
+    const maskedEmail = email.replace(/(^.).+(@.*$)/, '$1***$2');
     if (sendEmail !== false) {
       // Best-effort send. If SMTP isn't configured, log to error.log (dev path).
       const acceptUrl = _buildInviteUrl(req, /* siteConfig */ req.app.locals && req.app.locals.siteConfig, issued.token);