Secondary sort by entry type (events → tasks → notes) in calendar views

Add a secondary sort option in day, week, month, and year views that orders entries by type after the primary sort. For example: sort by time first, then for entries without a time (or as the type-grouping rule), show events first (with all-day events at the top), then tasks, then notes. Currently only a primary sort by time is available, leading to mixed ordering of types within the same view.