fix(frontend): replace unwrap() with expect() for better error messages

- console_log::init_with_level() now uses expect()
- web_sys::window() now uses expect() with helpful message
- window.document() now uses expect()
- document.body() now uses expect()

This provides meaningful error messages if WASM initialization fails.

frontend/src/lib.rs

@@ -11,11 +11,15 @@ use app::App;
 #[wasm_bindgen(start)]
 pub fn main() {
     console_error_panic_hook::set_once();
-    console_log::init_with_level(log::Level::Debug).unwrap();
+    console_log::init_with_level(log::Level::Debug)
+        .expect("Failed to initialize logging");
 
-    let window = web_sys::window().unwrap();
+    let window = web_sys::window()
-    let document = window.document().unwrap();
+        .expect("Failed to access window - browser may not be fully loaded");
-    let body = document.body().unwrap();
+    let document = window.document()
+        .expect("Failed to access document");
+    let body = document.body()
+        .expect("Failed to access document body");
     
     // Add app-loaded class to body to hide spinner via CSS
     let _ = body.class_list().add_1("app-loaded");