working compound days + working public holidays

Backend/models/workDay.go

@@ -23,6 +23,11 @@ type WorkDay struct {
 	worktimeAbsece Absence
 }
 
+// IsEmpty implements [IWorkDay].
+func (d *WorkDay) IsEmpty() bool {
+	return len(d.Bookings) == 0
+}
+
 type WorktimeBase int
 
 const (