feat: server-based version with menu flagging, distributed polling, and SSE

Complete implementation including:
- Express server with Bessa API proxy
- Puppeteer scraper for menu data
- Flag storage (file-based persistence)
- SSE manager for real-time updates
- Polling orchestrator for distributed polling
- Frontend with weekly view, ordering, and flagging UI
- Yellow/green glow indicators for flagged items

.env.example

@@ -0,0 +1,6 @@
+# Bessa Credentials (NEVER commit real credentials!)
+BESSA_EMPLOYEE_NUMBER=YOUR_EMPLOYEE_NUMBER
+BESSA_PASSWORD=YOUR_PASSWORD
+
+# Optional: Headless mode (set to false for debugging)
+PUPPETEER_HEADLESS=true