- Add getItemsByFilter server action with support for: - Priority filtering (low, medium, high) - Completed status filtering - Tag filtering with compound AND logic - Due date range filtering - Sorting by createdAt, dueDate, priority, and title - Ascending and descending sort order - Handle null due dates in sorting (placed at end) - Implement compound filter logic with AND conditions - Requirements: 6.1, 6.2, 6.3, 6.5