feat: implement PWA push notifications for daily sadhana reminders

[nitishchaubeyy]

📝 Problem Statement

Users often forget to log their daily Japs, leading to broken streaks and loss of engagement. We need a way to gently remind them to complete their sadhana.

🚀 Proposed Solution

Integrate the Web Push API to send daily reminders to the user's device (Mobile/Desktop) via the PWA service worker.

Key Changes:

• Service Worker: Update sw.js to handle incoming push events.
• Permissions: Add a "Enable Notifications" toggle in the User Settings.
• Backend: Setup a cron job (using Vercel Cron or Supabase Edge Functions) to trigger notifications at a specific time (e.g., 9:00 PM).
• Content: Simple message: "Nitish, kya aaj ki sadhana poori hui? Ek click mein log karein! 🏔️"

✅ Acceptance Criteria

• User receives a notification even when the browser is closed.
• Clicking the notification opens the Dashboard directly.
• Users can opt-out of notifications anytime.