Add print preview modal with hour range selection

Implements comprehensive print functionality for calendar views:
- Print preview modal with live preview and zoom controls
- Hour range selection for week view (start/end hours)
- Print-specific CSS to hide UI elements and optimize layout
- Event repositioning to align with visible time labels
- Support for both 30-minute and 15-minute time increments
- Mouse wheel zoom functionality in preview

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/components/mod.rs

@@ -13,6 +13,7 @@ pub mod external_calendar_modal;
 pub mod login;
 pub mod mobile_warning_modal;
 pub mod month_view;
+pub mod print_preview_modal;
 pub mod recurring_edit_modal;
 pub mod route_handler;
 pub mod sidebar;
@@ -32,6 +33,7 @@ pub use event_modal::EventModal;
 pub use login::Login;
 pub use mobile_warning_modal::MobileWarningModal;
 pub use month_view::MonthView;
+pub use print_preview_modal::PrintPreviewModal;
 pub use recurring_edit_modal::{RecurringEditAction, RecurringEditModal};
 pub use route_handler::RouteHandler;
 pub use sidebar::{Sidebar, Theme, ViewMode};