feat: onCellClick callback and highlight appointments for days

Author: sjbur

packages/devextreme-scss/scss/widgets/base/scheduler/views/year/_index.scss

@@ -29,8 +29,23 @@
             .dx-calendar-cell {
                 cursor: pointer;
 
+                &.dx-calendar-other-month {
+                    opacity: 0.5;
+                }
+
                 &:hover {
-                    background-color: $scheduler-workspace-hovered-cell-color;
+                    background-color: #f5f5f5;
+                }
+
+                .dx-scheduler-year-calendar-has-appointment {
+                    background-color: #337ab7;
+                    color: #fff;
+                    border-radius: 50%;
+                    display: inline-block;
+                    width: 1.5em;
+                    height: 1.5em;
+                    line-height: 1.5em;
+                    text-align: center;
                 }
             }
         }

packages/devextreme/js/__internal/scheduler/m_scheduler.ts

@@ -893,6 +893,10 @@ class Scheduler extends SchedulerOptionsBaseWidget {
     if (this._isAgenda()) {
       this._workSpace.renderAgendaLayout(viewModel);
     }
+
+    if (this.currentView.type === 'year') {
+      workspace.repaint();
+    }
   }
 
   _initExpressions(fields: IFieldExpr) {

packages/devextreme/js/__internal/scheduler/view_model/appointments_layout_manager.ts

@@ -39,6 +39,9 @@ class AppointmentLayoutManager {
 
   public generateViewModel(): AppointmentViewModelPlain[] {
     const viewType = this.schedulerStore.currentView.type;
+    if (viewType === 'year') {
+      return [];
+    }
     if (viewType === 'agenda') {
       const viewModel = generateAgendaViewModel(this.schedulerStore, this.filteredItems);
       return viewModel.map((item) => ({