frontend: rebuild bookmark page with drag-and-drop, search, and theme system

- bookmark management with dnd-kit reordering, bulk edit, search,
  category filter/rename, and meta auto-fetch
- migrate /bookmarks → /dashboard/bookmarks under (main) layout
- homepage redesign with category grid, /-key search, dock tooltips
- theme toggle + use-theme, sonner toasts, alert-dialog/skeleton,
  visual refresh of auth pages

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/app/login/page.tsx

@@ -1,7 +1,6 @@
-"use client";
-
-import { Suspense, useEffect } from "react";
-import { useRouter, useSearchParams } from "next/navigation";
+import type { Metadata } from "next";
+import { redirect } from "next/navigation";
+import { Suspense } from "react";
 import {
   Dialog,
   DialogContent,
@@ -10,41 +9,42 @@ import {
 } from "@/components/ui/dialog";
 import { LoginForm } from "./login-form";
 
+export const metadata: Metadata = {
+  title: "登录",
+};
+
 const hasKeycloak = !!process.env.AUTH_KEYCLOAK_ISSUER;
 
-function LoginPageContent() {
-  const router = useRouter();
-  const searchParams = useSearchParams();
-  const callbackUrl = searchParams.get("callbackUrl");
-  const error = searchParams.get("error");
+export default async function LoginPage({
+  searchParams,
+}: {
+  searchParams: Promise<{ [key: string]: string | string[] | undefined }>;
+}) {
+  const sp = await searchParams;
+  const callbackUrl = typeof sp.callbackUrl === "string" ? sp.callbackUrl : null;
+  const error = typeof sp.error === "string" ? sp.error : null;
 
-  useEffect(() => {
-    // If not an OAuth callback, redirect to home with login modal open
-    if (!callbackUrl && !error) {
-      router.replace("/?login=1");
-    }
-  }, [callbackUrl, error, router]);
+  if (!callbackUrl && !error) {
+    redirect("/?login=1");
+  }
 
   return (
-    <div className="flex min-h-screen items-center justify-center bg-gradient-to-br from-slate-50 to-slate-100 p-4">
+    <div className="flex min-h-screen items-center justify-center bg-gradient-to-br from-background via-background to-muted/40 p-4">
       <Dialog defaultOpen>
         <DialogContent className="sm:max-w-md">
           <DialogHeader>
             <DialogTitle className="text-center">登录</DialogTitle>
           </DialogHeader>
-          <Suspense fallback={<div>加载中...</div>}>
-            <LoginForm hasKeycloak={hasKeycloak} />
+          {error && (
+            <p className="rounded-md border border-destructive/30 bg-destructive/10 p-2 text-center text-xs text-destructive">
+              登录过程中出现错误,请重试
+            </p>
+          )}
+          <Suspense fallback={<div className="text-sm text-muted-foreground">加载中...</div>}>
+            <LoginForm hasKeycloak={hasKeycloak} callbackUrl={callbackUrl ?? undefined} />
           </Suspense>
         </DialogContent>
       </Dialog>
     </div>
   );
 }
-
-export default function LoginPage() {
-  return (
-    <Suspense fallback={<div className="flex min-h-screen items-center justify-center">加载中...</div>}>
-      <LoginPageContent />
-    </Suspense>
-  );
-}