Extract Email Delivery to Notification Service

[frogr]

Problem

Email sending is tightly coupled to business logic.

Tasks

• Create notification service abstraction
• Implement email notification adapter
• Extract email templates to presenters
• Add notification queue for async delivery

Acceptance Criteria

• Create app/services/notifications/ directory
• Email delivery decoupled from authentication
• Notification service with clear interface
• Support for multiple notification channels
• All mailer specs pass
• Add unit tests for notification service

Files to modify

• app/services/authentication_service.rb
• app/mailers/user_mailer.rb
• Create notification service structure

Phase: 3 (Infrastructure)
Priority: Medium