fix: restore essential UI components and resolve compilation errors after aggressive cleanup

frontend/src/components/ui/separator.rs

@@ -2,7 +2,6 @@ use leptos::prelude::*;
 use tailwind_fuse::tw_merge;
 
 #[derive(Clone, Copy, PartialEq, Eq, Default, Debug)]
-#[allow(dead_code)]
 pub enum SeparatorOrientation { #[default] Horizontal, Vertical }
 
 #[component]
@@ -10,13 +9,13 @@ pub fn Separator(
     #[prop(into, optional)] orientation: Signal<SeparatorOrientation>,
     #[prop(into, optional)] class: String,
 ) -> impl IntoView {
-    let class = tw_merge!(
+    let class_signal = move || tw_merge!(
         "shrink-0 bg-border",
-        move || match orientation.get() {
+        match orientation.get() {
             SeparatorOrientation::Horizontal => "h-[1px] w-full",
             SeparatorOrientation::Vertical => "h-full w-[1px]",
         },
-        class
+        class.clone()
     );
-    view! { <div class=class role="none" /> }
+    view! { <div class=class_signal role="none" /> }
 }