Persist calendar month across page refreshes using localStorage

- Load saved month from localStorage on calendar initialization
- Fall back to current date if no saved month exists
- Save current month to localStorage on all navigation actions:
  - Previous month navigation
  - Next month navigation
  - Today button clicks
- Use YYYY-MM-DD format for localStorage storage
- Maintain month view after page refreshes from event creation/editing
- Preserve user's selected month during manual browser refreshes

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

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

src/components/calendar.rs

@@ -4,6 +4,7 @@ use std::collections::HashMap;
 use crate::services::calendar_service::{CalendarEvent, UserInfo};
 use crate::components::EventModal;
 use wasm_bindgen::JsCast;
+use gloo_storage::{LocalStorage, Storage};
 
 #[derive(Properties, PartialEq)]
 pub struct CalendarProps {
@@ -23,7 +24,19 @@ pub struct CalendarProps {
 #[function_component]
 pub fn Calendar(props: &CalendarProps) -> Html {
     let today = Local::now().date_naive();
-    let current_month = use_state(|| today);
+    let current_month = use_state(|| {
+        // Try to load saved month from localStorage
+        if let Ok(saved_month_str) = LocalStorage::get::<String>("calendar_current_month") {
+            if let Ok(saved_month) = NaiveDate::parse_from_str(&saved_month_str, "%Y-%m-%d") {
+                // Return the first day of the saved month
+                saved_month.with_day(1).unwrap_or(today)
+            } else {
+                today
+            }
+        } else {
+            today
+        }
+    });
     let selected_day = use_state(|| today);
     let selected_event = use_state(|| None::<CalendarEvent>);
     
@@ -53,6 +66,8 @@ pub fn Calendar(props: &CalendarProps) -> Html {
             let prev = *current_month - Duration::days(1);
             let first_of_prev = prev.with_day(1).unwrap();
             current_month.set(first_of_prev);
+            // Save to localStorage
+            let _ = LocalStorage::set("calendar_current_month", first_of_prev.format("%Y-%m-%d").to_string());
         })
     };
     
@@ -65,6 +80,8 @@ pub fn Calendar(props: &CalendarProps) -> Html {
                 NaiveDate::from_ymd_opt(current_month.year(), current_month.month() + 1, 1).unwrap()
             };
             current_month.set(next);
+            // Save to localStorage
+            let _ = LocalStorage::set("calendar_current_month", next.format("%Y-%m-%d").to_string());
         })
     };
 
@@ -74,6 +91,8 @@ pub fn Calendar(props: &CalendarProps) -> Html {
             let today = Local::now().date_naive();
             let first_of_today_month = today.with_day(1).unwrap();
             current_month.set(first_of_today_month);
+            // Save to localStorage
+            let _ = LocalStorage::set("calendar_current_month", first_of_today_month.format("%Y-%m-%d").to_string());
         })
     };