feat(upload): add admin/ir role gate and admin layout

Author: William-Hill

codebenders-dashboard/app/admin/layout.tsx

@@ -0,0 +1,3 @@
+export default function AdminLayout({ children }: { children: React.ReactNode }) {
+  return <>{children}</>
+}

codebenders-dashboard/lib/roles.ts

@@ -11,6 +11,8 @@ export const ROUTE_PERMISSIONS: Array<{ prefix: string; roles: Role[] }> = [
   { prefix: "/api/courses",             roles: ["admin", "advisor", "ir", "faculty"] },
   { prefix: "/api/query-summary", roles: ["admin", "advisor", "ir", "faculty"] },
   { prefix: "/api/query-history/export", roles: ["admin", "ir"] },
+  { prefix: "/admin",                    roles: ["admin", "ir"] },
+  { prefix: "/api/admin",               roles: ["admin", "ir"] },
 ]
 
 export function canAccess(pathname: string, role: Role): boolean {