refactored broad range of the application, split files, modularized calendar and file views, centralized bottom sheets and clipboard handling, and implemented unit test coverage

lib/routing/app_routes.dart

@@ -29,7 +29,7 @@ import '../widget/user_avatar.dart';
 ///
 /// Every full-page push in modules should go through one of these methods.
 /// Dialogs (`showDialog`), bottom sheets (`showStickyFlexibleBottomSheet`,
-/// `showAppointmentBottomSheet`), and `Navigator.pop` for closing those
+/// `showDetailsBottomSheet`), and `Navigator.pop` for closing those
 /// remain unchanged and live at the call sites.
 class AppRoutes {
   AppRoutes._();