fix: add dotenv loading to migration script for production auth

scripts/migrate-value-pluralism-docs.js

@@ -7,6 +7,7 @@
  * configured to display in the docs.html sidebar.
  */
 
+require('dotenv').config();
 const { MongoClient } = require('mongodb');
 
 const MONGO_URI = process.env.MONGO_URI || 'mongodb://localhost:27017';