fix: upgrade to leptos 0.8 with compatible deps

- Update leptos-use from 0.15 to 0.16 for reactive_graph compatibility
- Fix web-sys ProgressElement -> ProgressEvent feature
- Resolve closure ownership issues in context_menu.rs and statusbar.rs
- Update Cargo dependencies for stable compilation

frontend/src/utils/notification.rs

@@ -1,7 +1,6 @@
 use wasm_bindgen::prelude::*;
 use web_sys::{Notification, NotificationOptions};
 use leptos::prelude::*;
-use reactive_graph::traits::Get; // Signal::get() için gerekli
 use leptos_use::{use_web_notification, UseWebNotificationReturn, NotificationPermission};
 
 /// Request browser notification permission from user
@@ -80,4 +79,4 @@ pub fn show_notification_if_enabled(title: &str, body: &str) -> bool {
     }
     
     false
-}
+}