הוספת התראות פוש דפדפן vapid

I want to add browser push notifications that work even when the site is closed, using VAPID keys.
Step 1 — Generate VAPID keys:
Run npx web-push generate-vapid-keys to generate a public and private key pair. If you can't run shell commands, create a backend script that runs this programmatically using the web-push package and outputs the keys. Then open the secrets/environment variables panel so I can paste them as VAPID_PUBLIC_KEY and VAPID_PRIVATE_KEY. Wait for me to confirm before continuing.
Step 2 — Build the notification system:
Create public/sw.js (service worker that handles push events and notification clicks), client-side subscription flow, backend sending logic, and a 🔔 toggle button in the UI. Use the VAPID keys from secrets.
Step 3 — Test:
Send a test notification to this specific device to verify everything works end to end.