fix: add dotenv to PDF generator for environment variable loading

- Added require('dotenv').config() to load .env file
- Enables MONGODB_URI and MONGODB_DB to be read from environment
- Required for script to work in production with authenticated MongoDB

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

scripts/generate-public-pdfs.js

@@ -4,6 +4,7 @@
  * Uses Puppeteer (headless Chrome) for PDF generation
  */
 
+require('dotenv').config();
 const { MongoClient } = require('mongodb');
 const puppeteer = require('puppeteer');
 const fs = require('fs').promises;