#1424 Add Popup UI for Web Push Subscription in Extension

[Anonymous]

Originally created by: GAURAVCHAWLA1808

This PR enhances the cookbook.push example by introducing a popup.html and popup.js to provide a user-friendly interface for managing push subscriptions. It addresses Issue [#1408] by ensuring a complete web push implementation with non-interactive subscription handling.

Additionally, this PR addresses the review feedback from PR [#1410] by isolating and implementing the requested changes separately.

Changes Implemented:
popup.html & popup.js:

User Interface for Subscription Management:
Added a simple UI with "Subscribe" and "Unsubscribe" buttons.
Displays the current subscription status to the user.
Service Worker Integration:
Ensures the service worker is ready before attempting push subscription.
Handles both subscribing and unsubscribing from push notifications.
Enhanced Logging & Error Handling:
Provides clear console logs for debugging.
Displays subscription status updates directly in the popup.
background.js:

Integrated with popup.js to ensure smooth communication between the popup and service worker.
Improved push subscription flow by ensuring userVisibleOnly: true.
This update ensures a fully functional web push example with a proper UI, making it easier for users to subscribe/unsubscribe without requiring manual DevTools interactions.