feat(toolrate): desktop topbar theme toggle + dark-mode amber/gold

- ThemeToggle moved from sidebar footer to new desktop topbar (top-right),
  page title shown left; mobile header + login unchanged
- dark theme primary switched from neon orange to amber/gold (38 92% 50%),
  primary-foreground to dark navy for contrast; ring + chart-1 harmonized
- light theme stays orange

artifacts/toolrate/src/components/layout.tsx

@@ -18,6 +18,10 @@ export function Layout({ children }: { children: React.ReactNode }) {
     ...(isAdmin ? [{ href: "/admin/redundancy", label: "Redundancy", icon: AlertTriangle }] : []),
   ];
 
+  const activeLink = links.find(
+    (link) => location === link.href || (link.href !== "/" && location.startsWith(link.href)),
+  );
+
   return (
     <div className="flex min-h-screen bg-background text-foreground">
       <aside className="w-64 border-r bg-card flex flex-col hidden md:flex">
@@ -44,10 +48,7 @@ export function Layout({ children }: { children: React.ReactNode }) {
           })}
         </nav>
 
-        <div className="p-4 border-t space-y-3">
-          <div className="flex justify-end">
-            <ThemeToggle />
-          </div>
+        <div className="p-4 border-t">
           {isLoading ? (
             <div className="flex items-center gap-3 px-3 py-2">
               <Skeleton className="w-8 h-8 rounded-full" />
@@ -96,6 +97,12 @@ export function Layout({ children }: { children: React.ReactNode }) {
       </aside>
 
       <main className="flex-1 flex flex-col min-w-0">
+        <header className="hidden md:flex items-center justify-between border-b bg-card px-6 py-3">
+          <h1 className="text-sm font-semibold text-muted-foreground">
+            {activeLink?.label ?? "ToolRate"}
+          </h1>
+          <ThemeToggle />
+        </header>
         <header className="md:hidden border-b p-4 flex items-center justify-between bg-card">
           <div className="flex items-center gap-2 text-primary font-bold text-lg">
             <Wrench className="w-5 h-5" />