frontend: redesign homepage with magic dock and login dialog

- Replace top login/register buttons with magic dock navigation
- Add dock items: home, downloads, blog, and conditional login/logout
- Show dashboard icon in dock when authenticated
- Extract HomePageClient for client-side dialog state

frontend/app/home-page-client.tsx

@@ -0,0 +1,76 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { useSearchParams } from "next/navigation";
+import { BlurFade } from "@/components/magicui/blur-fade";
+import { HomeDock } from "./home-dock";
+import {
+  Dialog,
+  DialogContent,
+  DialogHeader,
+  DialogTitle,
+} from "@/components/ui/dialog";
+import { LoginForm } from "./login/login-form";
+
+export function HomePageClient({
+  isAuthenticated,
+  healthText,
+  hasKeycloak,
+}: {
+  isAuthenticated: boolean;
+  healthText: string;
+  hasKeycloak: boolean;
+}) {
+  const searchParams = useSearchParams();
+  const [loginOpen, setLoginOpen] = useState(false);
+
+  useEffect(() => {
+    if (searchParams.get("login") === "1" && !isAuthenticated) {
+      setLoginOpen(true);
+    }
+  }, [searchParams, isAuthenticated]);
+
+  return (
+    <div className="relative flex min-h-screen flex-col items-center justify-center bg-gradient-to-br from-slate-50 to-slate-100 p-4 pb-24">
+      <BlurFade inView delay={0.1}>
+        <h1 className="mb-4 text-center text-4xl font-extrabold tracking-tight text-slate-900">
+          EvanPage
+        </h1>
+      </BlurFade>
+
+      <BlurFade inView delay={0.2}>
+        <p className="mb-8 max-w-md text-center text-lg text-slate-600">
+          全栈基础框架
+        </p>
+      </BlurFade>
+
+      <BlurFade inView delay={0.3}>
+        <div className="rounded-2xl border bg-white/80 px-8 py-6 shadow-lg backdrop-blur">
+          <p className="text-center text-sm font-medium text-slate-500">
+            后端状态
+          </p>
+          <p className="mt-2 text-center text-xl font-semibold text-slate-800">
+            {healthText}
+          </p>
+        </div>
+      </BlurFade>
+
+      <HomeDock
+        isAuthenticated={isAuthenticated}
+        onLoginClick={() => !isAuthenticated && setLoginOpen(true)}
+      />
+
+      <Dialog open={loginOpen} onOpenChange={setLoginOpen}>
+        <DialogContent className="sm:max-w-md">
+          <DialogHeader>
+            <DialogTitle className="text-center">登录</DialogTitle>
+          </DialogHeader>
+          <LoginForm
+            hasKeycloak={hasKeycloak}
+            onSuccess={() => setLoginOpen(false)}
+          />
+        </DialogContent>
+      </Dialog>
+    </div>
+  );
+}