Real-time Hacker News user & item watcher with Firebase SSE streaming and Web Push notifications.

• Watch HN users — get notified when they post, comment, or update their profile
• Watch HN items — track score changes, new comments on stories
• Real-time via Firebase SSE — changes pushed instantly when dashboard is open
• Web Push notifications — native browser notifications even when tab is closed
• Interval backup poller — catches everything every 5 minutes when browser is closed

Rendering mermaid diagram...

1. Open the dashboard and add HN usernames or item IDs to watch
2. The browser opens EventSource connections directly to Firebase for each watched entity
3. When Firebase pushes a put/patch event, the client-side diff engine detects changes
4. Changes are reported to the backend, stored in SQLite, and trigger Web Push notifications
5. When the browser is closed, the interval val polls every 5 minutes and sends push notifications

1. VAPID keys are pre-generated and stored as env vars
2. Open the dashboard and click "Enable Notifications" for Web Push
3. Add HN usernames (e.g. pg) or item IDs (e.g. 42424242) to watch

• VAPID_KEYS — ECDSA P-256 keypair in JWK format
• VAPID_SUBJECT — mailto: contact email for VAPID