feat: implement admin and OIDC authentication methods; add login and user info endpoints

Signed-off-by: Noste <83548733+Noooste@users.noreply.github.com>

frontend/src/components/auth/ProtectedRoute.tsx

@@ -0,0 +1,29 @@
+import { Navigate, useLocation } from 'react-router-dom';
+import { useAuthStore } from '@/store/auth-store';
+import { LoadingSpinner } from './LoadingSpinner';
+
+interface ProtectedRouteProps {
+  children: React.ReactNode;
+}
+
+export function ProtectedRoute({ children }: ProtectedRouteProps) {
+  const { isAuthenticated, isLoading, config } = useAuthStore();
+  const location = useLocation();
+
+  if (isLoading) {
+    return <LoadingSpinner />;
+  }
+
+  // If no auth is enabled, always allow access
+  if (config && !config.admin.enabled && !config.oidc.enabled) {
+    return <>{children}</>;
+  }
+
+  // If not authenticated, redirect to login with return URL
+  if (!isAuthenticated) {
+    const returnUrl = encodeURIComponent(location.pathname + location.search);
+    return <Navigate to={`/login?returnUrl=${returnUrl}`} replace />;
+  }
+
+  return <>{children}</>;
+}