Add Next.js frontend PWA

- Pages: login, register, tasks list, task detail
- Components: TaskCard, TaskForm, GroupSelector, StatusBadge, Header
- Tailwind CSS, dark/light mode, PWA manifest
- Running on :3001 via systemd

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/tasks/app/page.tsx

@@ -0,0 +1,24 @@
+"use client";
+
+import { useEffect } from "react";
+import { useRouter } from "next/navigation";
+import { useAuth } from "@/lib/auth";
+
+export default function Home() {
+  const { token } = useAuth();
+  const router = useRouter();
+
+  useEffect(() => {
+    if (token) {
+      router.replace("/tasks");
+    } else {
+      router.replace("/login");
+    }
+  }, [token, router]);
+
+  return (
+    <div className="flex items-center justify-center min-h-[60vh]">
+      <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-blue-600"></div>
+    </div>
+  );
+}