[Feature Request]: Setup `WorkManager` for fetching notifications

[theMr17]

Description

To keep users informed of their latest GitHub notifications, background fetching must be supported. Android's WorkManager is a suitable choice for periodic background tasks that survive app restarts and comply with system constraints.

Proposed Solution

• Implement a CoroutineWorker class (e.g., GitHubNotificationWorker) that:
  • Periodically fetches data from the GitHub Notifications API (https://api.github.com/notifications)
  • Parses and filters new/unread notifications
  • Triggers an Android system notification if new notifications are found
• Use PeriodicWorkRequestBuilder to schedule the worker to run every 15 minutes.
• Use appropriate retry and backoff policies for network failure.
• Inject necessary dependencies (e.g., GitHub API service) via Hilt or another DI framework.

Additional Context

• Requires authenticated access to GitHub API using OAuth2 or Personal Access Token (PAT).
• Ensure background permissions and battery optimizations are handled gracefully.
• Consider using exponential backoff for reliability in unstable network conditions.