Implement Email Notification Digest System

[Techhackontime999]

Description

Build an email digest system that batches and sends periodic emails for missed notifications, new jobs, and connection requests - using Celery for async task scheduling.

Requirements

• Digest types: instant (current), daily, weekly (configurable per user)
• Daily digest: send at 8:00 AM user's local time
• Weekly digest: send Monday morning
• Email content: grouped notifications, new jobs matching alerts, connection requests, post engagement
• Email templates: professional HTML email with LinkUp branding
• Celery Beat schedule for periodic sending
• Unsubscribe link in every email
• Digest preference per notification type

Files to Create/Modify

• linkup/messaging/models.py - Add DigestPreference model
• linkup/messaging/tasks.py - New Celery tasks for digest generation and sending
• linkup/messaging/email_service.py - Email composition and sending service
• linkup/templates/email/daily_digest.html - Daily digest email template
• linkup/templates/email/weekly_digest.html - Weekly digest email template
• linkup/professional_network/settings/base.py - Celery beat schedule

Acceptance Criteria

• Users can choose digest frequency (instant/daily/weekly)
• Daily digests send at the correct local time
• Email content groups related notifications
• Unsubscribe link works
• Celery tasks run on schedule