fix(sidebar): pin to viewport height so footer stays visible

src/components/layout/Sidebar.tsx

@@ -77,7 +77,7 @@ export function Sidebar({ pets }: SidebarProps) {
   const [postTypeSheetOpen, setPostTypeSheetOpen] = useState(false);
 
   return (
-    <nav className="hidden lg:flex flex-col w-[240px] min-h-screen bg-card border-r border shrink-0">
+    <nav className="hidden lg:flex flex-col w-[240px] h-screen sticky top-0 bg-card border-r border shrink-0 overflow-y-auto">
       {/* Wordmark */}
       <div className="flex items-center gap-2 px-4 py-5">
         <PawPrint className="h-5 w-5 text-orange-500" aria-hidden="true" />