Remove unnecessary frontend console logs

- Remove app rendering auth_token debug logs
- Remove auth token validation success message
- Remove recurring event occurrence generation logs
- Remove exception dates logging for VEvents

Frontend now runs with minimal essential logging.

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

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

frontend/src/app.rs

@@ -71,7 +71,6 @@ pub fn App() -> Html {
                     match auth_service.verify_token(&stored_token).await {
                         Ok(true) => {
                             // Token is valid, set it
-                            web_sys::console::log_1(&"✅ Stored auth token is valid".into());
                             auth_token.set(Some(stored_token));
                         }
                         _ => {
@@ -1198,10 +1197,6 @@ pub fn App() -> Html {
         })
     };
 
-    // Debug logging
-    web_sys::console::log_1(
-        &format!("App rendering: auth_token = {:?}", auth_token.is_some()).into(),
-    );
 
     html! {
         <BrowserRouter>