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/index.html

@@ -6,6 +6,8 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <base data-trunk-public-url />
     <link data-trunk rel="css" href="styles.css">
+    <link data-trunk rel="css" href="print.css">
+    <link data-trunk rel="css" href="print-preview.css">
     <link data-trunk rel="copy-file" href="styles/google.css">
     <link data-trunk rel="icon" href="favicon.ico">
 </head>