- Add default campaign email template to DefaultTemplates.php - Add toggle settings (campaign_scheduling, subscriber_limit_enabled) - Add public unsubscribe endpoint with secure token verification - Update CampaignManager to use NewsletterController unsubscribe URLs - Add generate_unsubscribe_url() helper for email templates
- Add CampaignManager.php with CPT registration, CRUD, batch sending - Add CampaignsController.php with 8 REST endpoints (list, create, get, update, delete, send, test, preview) - Register newsletter_campaign event in EventRegistry for email template - Initialize CampaignManager in Bootstrap.php - Register routes in Routes.php