feat: implement auth state management with RouteGuards

frontend/src/components/RouteGuards.tsx

@@ -0,0 +1,38 @@
+import { Navigate, useLocation } from "react-router-dom";
+import { ROUTES } from "../config/routes";
+import { useAuth } from "../hooks/useAuth";
+import SplashScreen from "./SplashScreen";
+
+/**
+ * Post-login routes.
+ * Redirects to /login if not already authenticated.
+ */
+export function ProtectedRoute({ children }: { children: React.ReactNode }) {
+  const { isAuthenticated, isInitializing } = useAuth();
+  const location = useLocation();
+
+  if (isInitializing) return <SplashScreen />;
+
+  if (!isAuthenticated) {
+    // Save the intended location to redirect back after login
+    return <Navigate to="/login" state={{ from: location }} replace />;
+  }
+
+  return <>{children}</>;
+}
+
+/**
+ * Pre-login flows.
+ * Redirects to /drawer if already authenticated.
+ */
+export function PublicRoute({ children }: { children: React.ReactNode }) {
+  const { isAuthenticated, isInitializing } = useAuth();
+
+  if (isInitializing) return <SplashScreen />;
+
+  if (isAuthenticated) {
+    return <Navigate to={ROUTES.DRAWER} replace />;
+  }
+
+  return <>{children}</>;
+}

frontend/src/components/SplashScreen.tsx

@@ -0,0 +1,17 @@
+import Logo from "./Logo";
+
+export default function SplashScreen() {
+  return (
+    <div className="fixed inset-0 bg-base-100 flex flex-col items-center justify-center z-9999">
+      <div className="flex flex-col items-center gap-6 animate-pulse">
+        <Logo />
+        <div className="flex flex-col items-center gap-2">
+          <span className="loading loading-ring loading-lg text-primary" />
+          <p className="text-xs uppercase tracking-widest opacity-40 font-display">
+            Initializing Identity
+          </p>
+        </div>
+      </div>
+    </div>
+  );
+}