Add collapsed sidebar section dividers

src/components/Layout.tsx

@@ -118,7 +118,12 @@ const Layout = () => {
 
         <nav className="flex-1 space-y-5 overflow-y-auto px-3 py-4">
           {navigationSections.map((section) => (
-            <div key={section.label} className="space-y-1.5">
+            <div
+              key={section.label}
+              className={`space-y-1.5 ${
+                isSidebarCollapsed ? 'border-t border-dark-border pt-5 first:border-t-0 first:pt-0' : ''
+              }`}
+            >
               {!isSidebarCollapsed && (
                 <div className="px-3 pb-1 text-[11px] font-bold uppercase tracking-widest text-dark-muted">
                   {section.label}