Push notifications for session end and streak reminders

[sonnymay]

Summary

FocusMon runs in the background during sessions, but users have no way to know when a session ends unless they're watching the screen. Push notifications would improve usability significantly for a focus app.

Acceptance criteria

• Local notification fires when a focus session timer reaches zero (Expo Notifications API)
• Daily streak reminder notification at a user-configured time (default 9 AM)
• Notification permission requested on first launch with a clear explanation
• Notification settings screen: enable/disable session-end and streak-reminder separately; configure reminder time
• Notifications work when the app is backgrounded (not killed)
• iOS and Android both tested via Expo Go

Stack

expo-notifications · expo-task-manager for background scheduling