feat(frontend): add mentor chat and admin studio

Ship realtime mentor messaging and staff control panels for curriculum, users, and registration gates.

frontend/src/components/admin/list-toolbar.tsx

@@ -0,0 +1,38 @@
+import type { ReactNode, SelectHTMLAttributes } from "react";
+import { cn } from "@/lib/utils";
+
+/** Shared chrome for admin list search / filter rows. */
+export function ListToolbar({
+  children,
+  className,
+}: {
+  children: ReactNode;
+  className?: string;
+}) {
+  return (
+    <div
+      className={cn(
+        "flex flex-wrap items-center gap-2.5 border-b border-border pb-4",
+        className,
+      )}
+    >
+      {children}
+    </div>
+  );
+}
+
+/** Native select styled to match Input height and radius. */
+export function AdminSelect({
+  className,
+  ...props
+}: SelectHTMLAttributes<HTMLSelectElement>) {
+  return (
+    <select
+      className={cn(
+        "h-11 rounded-lg border border-input bg-card px-3 font-sans text-sm outline-none transition-colors focus-visible:ring-2 focus-visible:ring-ring disabled:cursor-not-allowed disabled:opacity-50",
+        className,
+      )}
+      {...props}
+    />
+  );
+}