Refactor calendar V2 core with DI and new features

Introduces dependency injection container and composition root
Adds core services like DateService and NavigationAnimator
Simplifies CalendarOrchestrator with improved store handling
Implements mock stores and demo application for V2 calendar

wwwroot/css/calendar-v2.css

@@ -107,6 +107,22 @@ swp-grid-container {
   overflow: hidden;
 }
 
+/* Viewport/Track for slide animation */
+swp-header-viewport,
+swp-content-viewport {
+  overflow: hidden;
+}
+
+swp-header-track,
+swp-content-track {
+  display: flex;
+}
+
+swp-header-track > swp-calendar-header,
+swp-content-track > swp-scrollable-content {
+  flex: 0 0 100%;
+}
+
 /* Header */
 swp-calendar-header {
   display: grid;