Fix calendar event fetching to use visible date range

Moved event fetching logic from CalendarView to Calendar component to properly
use the visible date range instead of hardcoded current month. The Calendar
component already tracks the current visible date through navigation, so events
now load correctly for August and other months when navigating.

Changes:
- Calendar component now manages its own events state and fetching
- Event fetching responds to current_date changes from navigation
- CalendarView simplified to just render Calendar component
- Fixed cargo fmt/clippy formatting across codebase

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

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

frontend/src/auth.rs

@@ -34,14 +34,14 @@ impl AuthService {
         let base_url = option_env!("BACKEND_API_URL")
             .unwrap_or("http://localhost:3000/api")
             .to_string();
-        
+
         Self { base_url }
     }
 
     pub async fn login(&self, request: CalDAVLoginRequest) -> Result<AuthResponse, String> {
         self.post_json("/auth/login", &request).await
     }
-    
+
     // Helper method for POST requests with JSON body
     async fn post_json<T: Serialize, R: for<'de> Deserialize<'de>>(
         &self,
@@ -49,9 +49,9 @@ impl AuthService {
         body: &T,
     ) -> Result<R, String> {
         let window = web_sys::window().ok_or("No global window exists")?;
-        
-        let json_body = serde_json::to_string(body)
-            .map_err(|e| format!("JSON serialization failed: {}", e))?;
+
+        let json_body =
+            serde_json::to_string(body).map_err(|e| format!("JSON serialization failed: {}", e))?;
 
         let opts = RequestInit::new();
         opts.set_method("POST");
@@ -62,23 +62,27 @@ impl AuthService {
         let request = Request::new_with_str_and_init(&url, &opts)
             .map_err(|e| format!("Request creation failed: {:?}", e))?;
 
-        request.headers().set("Content-Type", "application/json")
+        request
+            .headers()
+            .set("Content-Type", "application/json")
             .map_err(|e| format!("Header setting failed: {:?}", e))?;
 
         let resp_value = JsFuture::from(window.fetch_with_request(&request))
             .await
             .map_err(|e| format!("Network request failed: {:?}", e))?;
 
-        let resp: Response = resp_value.dyn_into()
+        let resp: Response = resp_value
+            .dyn_into()
             .map_err(|e| format!("Response cast failed: {:?}", e))?;
 
-        let text = JsFuture::from(resp.text()
-            .map_err(|e| format!("Text extraction failed: {:?}", e))?)
-            .await
-            .map_err(|e| format!("Text promise failed: {:?}", e))?;
+        let text = JsFuture::from(
+            resp.text()
+                .map_err(|e| format!("Text extraction failed: {:?}", e))?,
+        )
+        .await
+        .map_err(|e| format!("Text promise failed: {:?}", e))?;
 
-        let text_string = text.as_string()
-            .ok_or("Response text is not a string")?;
+        let text_string = text.as_string().ok_or("Response text is not a string")?;
 
         if resp.ok() {
             serde_json::from_str::<R>(&text_string)
@@ -92,4 +96,4 @@ impl AuthService {
             }
         }
     }
-}
+}