Introduces Mattermost as a new notification channel, including backend service integration, controller validation, UI form fields, and updates to channel type enums in the database schema and migrations. This enables users to configure and send notifications via Mattermost webhooks.
Moved admin/user isolation checks and related methods from Domain and NotificationGroup models to User model for better separation of concerns. Replaced direct database queries in controllers and services with new model methods. Added methods for assigning unassigned domains/groups, searching domains, and clearing old notification logs. Updated views for improved UI consistency.
Introduces a new 'Webhook (Custom)' notification channel allowing users to send JSON payloads to any HTTP endpoint (e.g., n8n, Zapier, custom APIs). Updates the UI to support webhook configuration, adds backend validation, and implements the WebhookChannel for sending notifications. Documentation is updated with usage instructions and payload examples.
Refactored error log model and views to use a unified 'notes' field instead of 'resolution_notes'. Added a modal dialog for entering resolution notes when marking errors as resolved in admin views. Improved stack trace handling in ErrorHandler by storing as JSON and formatting for display. Expanded NotificationService to support multi-channel notifications (email, Telegram, Discord, Slack), group notifications, and improved domain expiration alerts.
