- Modify header template to use explicit `cancel_url` parameter
- Add `cancel_url` to new timer and HTTP function templates
- Remove default URL fallback in header template
- Add comprehensive routes for creating, editing, deleting, and toggling timer functions
- Create new HTML templates for timer function overview, new, and edit pages
- Extend Mithril editor component to support timer-specific settings like trigger type, frequency, and enabled status
- Implement database schema and versioning for timer functions
- Add UI improvements for timer function listing with detailed schedule and status information
