fix(frontend): robust loading spinner removal using css class

frontend/src/lib.rs

@@ -14,6 +14,12 @@ pub fn main() {
 
     let window = web_sys::window().unwrap();
     let document = window.document().unwrap();
+    let body = document.body().unwrap();
+    
+    // Add app-loaded class to body to hide spinner via CSS
+    let _ = body.class_list().add_1("app-loaded");
+
+    // Also try to remove it directly
     if let Some(loader) = document.get_element_by_id("app-loading") {
         loader.remove();
     }