Clean up debug logging and fix compiler warnings

- Remove non-critical debug logs from backend CalDAV parsing
- Remove all-day event debug logs from frontend components
- Fix unused variable warnings with underscore prefixes
- Keep essential logging while reducing noise

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

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

frontend/src/components/month_view.rs

@@ -113,6 +113,7 @@ pub fn month_view(props: &MonthViewProps) -> Html {
         "#3B82F6".to_string()
     };
 
+    
     html! {
         <div class="calendar-grid">
             // Weekday headers