feat: 添加注销账号功能

- 在个人资料页面添加注销账号按钮
- 需要输入用户名确认才能删除
- 删除所有用户数据：牌组、卡片、笔记、关注等
- 添加 8 种语言翻译

src/app/(auth)/users/[username]/DeleteAccountButton.tsx

@@ -0,0 +1,100 @@
+"use client";
+
+import { useState } from "react";
+import { useRouter } from "next/navigation";
+import { useTranslations } from "next-intl";
+import { toast } from "sonner";
+import { Button } from "@/design-system/base/button";
+import { Modal } from "@/design-system/overlay/modal";
+import { actionDeleteAccount } from "@/modules/auth/auth-action";
+
+interface DeleteAccountButtonProps {
+  username: string;
+}
+
+export function DeleteAccountButton({ username }: DeleteAccountButtonProps) {
+  const t = useTranslations("user_profile");
+  const router = useRouter();
+  const [showModal, setShowModal] = useState(false);
+  const [confirmUsername, setConfirmUsername] = useState("");
+  const [loading, setLoading] = useState(false);
+
+  const handleDelete = async () => {
+    if (confirmUsername !== username) {
+      toast.error(t("deleteAccount.usernameMismatch"));
+      return;
+    }
+
+    setLoading(true);
+    try {
+      const result = await actionDeleteAccount();
+      if (result.success) {
+        toast.success(t("deleteAccount.success"));
+        router.push("/");
+      } else {
+        toast.error(result.message || t("deleteAccount.failed"));
+      }
+    } catch {
+      toast.error(t("deleteAccount.failed"));
+    } finally {
+      setLoading(false);
+      setShowModal(false);
+    }
+  };
+
+  return (
+    <>
+      <Button variant="error" onClick={() => setShowModal(true)}>
+        {t("deleteAccount.button")}
+      </Button>
+
+      <Modal open={showModal} onClose={() => setShowModal(false)}>
+        <div className="p-6">
+          <h2 className="text-xl font-bold text-red-600 mb-4">
+            {t("deleteAccount.title")}
+          </h2>
+          
+          <div className="space-y-4">
+            <p className="text-gray-700">
+              {t("deleteAccount.warning")}
+            </p>
+            
+            <ul className="list-disc list-inside text-gray-600 text-sm space-y-1">
+              <li>{t("deleteAccount.warningDecks")}</li>
+              <li>{t("deleteAccount.warningCards")}</li>
+              <li>{t("deleteAccount.warningHistory")}</li>
+              <li>{t("deleteAccount.warningPermanent")}</li>
+            </ul>
+
+            <div className="mt-4">
+              <label className="block text-sm font-medium text-gray-700 mb-2">
+                {t("deleteAccount.confirmLabel")} <span className="font-mono font-bold">{username}</span>
+              </label>
+              <input
+                type="text"
+                value={confirmUsername}
+                onChange={(e) => setConfirmUsername(e.target.value)}
+                className="w-full px-3 py-2 border border-gray-300 rounded-md focus:outline-none focus:ring-2 focus:ring-red-500"
+                placeholder={username}
+              />
+            </div>
+          </div>
+
+          <div className="flex justify-end gap-3 mt-6">
+            <Button variant="secondary" onClick={() => setShowModal(false)}>
+              {t("deleteAccount.cancel")}
+            </Button>
+            <Button 
+              variant="error" 
+              onClick={handleDelete} 
+              loading={loading}
+              disabled={confirmUsername !== username}
+            >
+              {t("deleteAccount.confirm")}
+            </Button>
+          </div>
+        </div>
+      </Modal>
+    </>
+  );
+}

src/app/(auth)/users/[username]/page.tsx

@@ -10,6 +10,7 @@ import { getTranslations } from "next-intl/server";
 import { auth } from "@/auth";
 import { headers } from "next/headers";
 import { FollowStats } from "@/components/follow/FollowStats";
+import { DeleteAccountButton } from "./DeleteAccountButton";
 
 interface UserPageProps {
     params: Promise<{ username: string; }>;
@@ -45,7 +46,14 @@ export default async function UserPage({ params }: UserPageProps) {
             <div className="bg-white rounded-lg shadow-md p-6 mb-6">
                 <div className="flex items-center justify-between mb-4">
                     <div></div>
-                    {isOwnProfile && <LinkButton href="/logout">{t("logout")}</LinkButton>}
+                    <div className="flex items-center gap-3">
+                        {isOwnProfile && (
+                            <>
+                                <LinkButton href="/logout">{t("logout")}</LinkButton>
+                                <DeleteAccountButton username={username} />
+                            </>
+                        )}
+                    </div>
                 </div>
                 <div className="flex flex-col sm:flex-row items-start sm:items-center space-y-4 sm:space-y-0 sm:space-x-6">
                     {user.image ? (

src/modules/auth/auth-action-dto.ts

@@ -61,3 +61,8 @@ export type ActionOutputUserProfile = {
         updatedAt: Date;
     };
 };
+
+export type ActionOutputDeleteAccount = {
+    success: boolean;
+    message: string;
+};

src/modules/auth/auth-action.ts

@@ -5,11 +5,13 @@ import { headers } from "next/headers";
 import { redirect } from "next/navigation";
 import { ValidateError } from "@/lib/errors";
 import { createLogger } from "@/lib/logger";
+import { prisma } from "@/lib/db";
 import {
     ActionInputGetUserProfileByUsername,
     ActionInputSignIn,
     ActionInputSignUp,
     ActionOutputAuth,
+    ActionOutputDeleteAccount,
     ActionOutputUserProfile,
     validateActionInputGetUserProfileByUsername,
     validateActionInputSignIn,
@@ -180,3 +182,91 @@ export async function actionGetUserProfileByUsername(dto: ActionInputGetUserProf
         };
     }
 }
+
+/**
+ * Delete account action
+ * Permanently deletes the current user and all associated data
+ */
+export async function actionDeleteAccount(): Promise<ActionOutputDeleteAccount> {
+    try {
+        const session = await auth.api.getSession({ headers: await headers() });
+        if (!session?.user?.id) {
+            return { success: false, message: "Unauthorized" };
+        }
+
+        const userId = session.user.id;
+
+        await prisma.$transaction(async (tx) => {
+            // Delete in correct order to avoid foreign key constraints
+            // 1. Revlogs (depend on cards)
+            await tx.revlog.deleteMany({
+                where: { card: { note: { userId } } }
+            });
+
+            // 2. Cards (depend on notes and decks)
+            await tx.card.deleteMany({
+                where: { note: { userId } }
+            });
+
+            // 3. Notes (depend on note types)
+            await tx.note.deleteMany({
+                where: { userId }
+            });
+
+            // 4. Note types
+            await tx.noteType.deleteMany({
+                where: { userId }
+            });
+
+            // 5. Deck favorites
+            await tx.deckFavorite.deleteMany({
+                where: { userId }
+            });
+
+            // 6. Decks
+            await tx.deck.deleteMany({
+                where: { userId }
+            });
+
+            // 7. Follows (both as follower and following)
+            await tx.follow.deleteMany({
+                where: {
+                    OR: [
+                        { followerId: userId },
+                        { followingId: userId }
+                    ]
+                }
+            });
+
+            // 8. Dictionary lookups
+            await tx.dictionaryLookUp.deleteMany({
+                where: { userId }
+            });
+
+            // 9. Translation history
+            await tx.translationHistory.deleteMany({
+                where: { userId }
+            });
+
+            // 10. Sessions
+            await tx.session.deleteMany({
+                where: { userId }
+            });
+
+            // 11. Accounts
+            await tx.account.deleteMany({
+                where: { userId }
+            });
+
+            // 12. Finally, delete the user
+            await tx.user.delete({
+                where: { id: userId }
+            });
+        });
+
+        return { success: true, message: "Account deleted successfully" };
+    } catch (e) {
+        log.error("Delete account failed", { error: e });
+        return { success: false, message: "Failed to delete account" };
+    }
+}