feat: 评论/帖子编辑历史与编辑标记，内容锁定

- 新增 smartDiff 差异计算与 EditHistoryModal 编辑历史弹窗，替换原 CommentEditHistoryModal
- 新增 PostEditedMark 编辑标记展示
- 新增内容锁定机制（content_lock）防止并发编辑冲突
- 审核与通知服务适配

frontend/app/admin/announcements/AnnouncementComposeClient.tsx

@@ -21,6 +21,9 @@ import { ANNOUNCEMENT_COLORS, announcementPublicPath } from "./announcementColor
 type PublishKey = "published" | "draft";
 type StatusFilter = "all" | "published" | "draft";
 
+/** 公告正文字符上限（与后端 service/announcement.go 校验一致） */
+const CONTENT_MAX = 20000;
+
 type FormState = {
   title: string;
   content: string;
@@ -328,8 +331,9 @@ export default function AnnouncementComposeClient({
               value={form.content}
               onChange={(content) => {
                 setErrors((prev) => ({ ...prev, content: undefined }));
-                patchForm({ content });
+                patchForm({ content: content.slice(0, CONTENT_MAX) });
               }}
+              maxChars={CONTENT_MAX}
               allowHide
               allowReplyHide={false}
               placeholder="请输入公告正文，支持 Markdown…"

frontend/app/admin/badges/BadgesClient.tsx

@@ -200,7 +200,7 @@ export default function BadgesClient() {
             管理员自定义徽章：全站作者处展示前 2 枚，个人主页展示徽章墙；授予后用户会收到站内通知。
           </p>
         </div>
-        <button type="button" className="btn btn-solid btn-sm" onClick={openCreate}>
+        <button type="button" className="btn btn-primary btn-sm" onClick={openCreate}>
           <Plus size={14} /> 新建徽章
         </button>
       </div>
@@ -290,7 +290,7 @@ export default function BadgesClient() {
                   ) : (
                     <button
                       type="button"
-                      className="btn btn-solid btn-sm"
+                      className="btn btn-primary btn-sm"
                       disabled={grantingId === u.id}
                       onClick={() => void grant(u.id)}
                     >
@@ -416,7 +416,7 @@ export default function BadgesClient() {
           </button>
           <button
             type="button"
-            className="btn btn-solid btn-sm"
+            className="btn btn-primary btn-sm"
             disabled={saving || runeCount(form.name.trim()) === 0}
             onClick={() => void saveForm()}
           >

frontend/app/admin/content/ContentAdmin.tsx

@@ -25,6 +25,7 @@ import {
   apiAdminContentPosts,
   apiAdminContentComments,
   apiAdminSoftDeletePost,
+  apiCommentHistory,
   apiAdminRestorePost,
   apiAdminPurgePost,
   apiAdminSoftDeleteComment,
@@ -48,7 +49,7 @@ import AutolinkText from "@/components/AutolinkText";
 import ConfirmDialog from "@/components/ConfirmDialog";
 import StaffDeletePostModal from "@/components/StaffDeletePostModal";
 import DeleteCommentModal from "@/components/DeleteCommentModal";
-import CommentEditHistoryModal from "@/components/CommentEditHistoryModal";
+import EditHistoryModal from "@/components/EditHistoryModal";
 import {
   AdminEmpty,
   AdminPageHeader,
@@ -320,6 +321,7 @@ export default function ContentAdmin({
   const [staffDeleteComment, setStaffDeleteComment] = useState<AdminContentComment | null>(null);
   const [staffDeleteCommentBusy, setStaffDeleteCommentBusy] = useState(false);
   const [historyCommentId, setHistoryCommentId] = useState<number | null>(null);
+  const [historyCommentContent, setHistoryCommentContent] = useState("");
 
   const refreshCounts = useCallback(() => {
     apiAdminContentCounts().then(setCounts).catch(() => {});
@@ -710,11 +712,17 @@ export default function ContentAdmin({
                       onReject={() => askReject("comments", c.id)}
                     />
                   ) : null}
-                  <ContentAction
-                    label="历史"
-                    icon={<History size={13} />}
-                    onClick={() => setHistoryCommentId(c.id)}
-                  />
+                  {/* 未编辑（无修订快照）的评论不展示历史入口，避免打开空记录 */}
+                  {c.edited ? (
+                    <ContentAction
+                      label="历史"
+                      icon={<History size={13} />}
+                      onClick={() => {
+                        setHistoryCommentContent(c.content);
+                        setHistoryCommentId(c.id);
+                      }}
+                    />
+                  ) : null}
                   {c.deleted ? (
                     <>
                       {canModerateAuthor({ role: viewerRole }, c.user?.role) ? (
@@ -930,9 +938,14 @@ export default function ContentAdmin({
         }}
       />
 
-      <CommentEditHistoryModal
+      <EditHistoryModal
         open={historyCommentId != null}
-        commentId={historyCommentId}
+        title="评论编辑历史"
+        currentContent={historyCommentContent}
+        fetchPage={(p, s) => {
+          if (historyCommentId == null) return Promise.reject(new Error("未选择评论"));
+          return apiCommentHistory(historyCommentId, p, s);
+        }}
         onClose={() => setHistoryCommentId(null)}
       />
     </div>

frontend/app/admin/pages/PageComposeClient.tsx

@@ -20,6 +20,9 @@ import useUnsavedGuard from "@/hooks/useUnsavedGuard";
 type PublishKey = "published" | "draft";
 type StatusFilter = "all" | "published" | "draft";
 
+/** 单页正文字符上限（与后端 service/site_page.go 校验一致） */
+const CONTENT_MAX = 20000;
+
 type FormState = {
   slug: string;
   title: string;
@@ -365,8 +368,9 @@ export default function PageComposeClient({
               value={form.content}
               onChange={(content) => {
                 setErrors((prev) => ({ ...prev, content: undefined }));
-                patchForm({ content });
+                patchForm({ content: content.slice(0, CONTENT_MAX) });
               }}
+              maxChars={CONTENT_MAX}
               allowHide={false}
               placeholder="请输入页面正文，支持 Markdown…"
               rows={16}

frontend/app/admin/points/PointsTabs.tsx

@@ -56,7 +56,7 @@ export default function PointsTabs({
     : TAB_OPTIONS.filter((o) => o.key === "overview");
 
   return (
-    <div>
+    <div className={tab === "users" ? "admin-points-users-tab" : undefined}>
       {canManage ? (
         <div className="mb-4">
           <AdminSegmented

frontend/app/admin/points/UserPointsTab.tsx

@@ -24,6 +24,15 @@ const fmt = (n?: number) => (Number(n) || 0).toLocaleString("zh-CN");
 
 type PointsSortKey = "id" | "points" | "total_points";
 
+/**
+ * 表头吸顶样式：sticky 相对 .admin-canvas 滚动口生效（lg 起外层不再是滚动容器，见下方包装层）。
+ * 分隔线用 inset 阴影而非 border——border-collapse: collapse 下吸顶 th 的边线会丢失。
+ */
+const thStickStyle = {
+  background: "var(--panel)",
+  boxShadow: "inset 0 -1px 0 var(--line)",
+} as const;
+
 /** 表头排序按钮：未激活显示双向箭头，激活显示单向箭头并高亮 */
 function SortHeader({
   label,
@@ -158,24 +167,40 @@ export default function UserPointsTab() {
         />
       </div>
 
-      <div className="panel p-0 overflow-hidden">
-        <div className="overflow-x-auto">
+      <div className="panel p-0">
+        {/* lg 起放开横向滚动容器：sticky th 才能相对 admin-canvas 吸顶；窄屏保留横向滚动（不吸顶） */}
+        <div className="overflow-x-auto lg:overflow-x-visible">
           <table className="w-full text-[13px]" style={{ borderCollapse: "collapse" }}>
             <thead>
-              <tr style={{ borderBottom: "1px solid var(--line)" }}>
-                <th className="px-4 py-2.5 text-left font-medium" style={{ color: "var(--ink-3)" }}>
+              <tr>
+                <th
+                  className="sticky top-0 z-10 px-4 py-2.5 text-left font-medium"
+                  style={{ color: "var(--ink-3)", ...thStickStyle }}
+                >
                   用户
                 </th>
-                <th className="px-4 py-2.5 text-right font-medium" style={{ color: "var(--ink-3)" }}>
+                <th
+                  className="sticky top-0 z-10 px-4 py-2.5 text-right font-medium"
+                  style={{ color: "var(--ink-3)", ...thStickStyle }}
+                >
                   <SortHeader label="余额" active={sort === "points"} dir={dir} onClick={() => toggleSort("points")} />
                 </th>
-                <th className="px-4 py-2.5 text-right font-medium" style={{ color: "var(--ink-3)" }}>
+                <th
+                  className="sticky top-0 z-10 px-4 py-2.5 text-right font-medium"
+                  style={{ color: "var(--ink-3)", ...thStickStyle }}
+                >
                   <SortHeader label="累计获得" active={sort === "total_points"} dir={dir} onClick={() => toggleSort("total_points")} />
                 </th>
-                <th className="px-4 py-2.5 text-left font-medium" style={{ color: "var(--ink-3)" }}>
+                <th
+                  className="sticky top-0 z-10 px-4 py-2.5 text-left font-medium"
+                  style={{ color: "var(--ink-3)", ...thStickStyle }}
+                >
                   等级
                 </th>
-                <th className="px-4 py-2.5 text-right font-medium" style={{ color: "var(--ink-3)" }}>
+                <th
+                  className="sticky top-0 z-10 px-4 py-2.5 text-right font-medium"
+                  style={{ color: "var(--ink-3)", ...thStickStyle }}
+                >
                   操作
                 </th>
               </tr>

frontend/app/admin/settings/AccessSettings.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { ExternalLink, LogIn, MessageSquare, MessagesSquare, ShieldCheck, ShieldOff, Timer } from "lucide-react";
+import { ExternalLink, LogIn, MessageSquare, MessagesSquare, ShieldCheck, ShieldOff, Timer, Lock, Hourglass, Coins, History } from "lucide-react";
 import { useState } from "react";
 import {
   AdminSettingsGroup,
@@ -18,6 +18,59 @@ function InstantNote({ saving }: { saving?: boolean }) {
   return <span className="admin-settings-instant">{saving ? "正在保存…" : "修改后立即生效"}</span>;
 }
 
+/** 内容锁定 4 键（小时上限 8760 / 积分上限 100，后端裁剪） */
+type LockKeys = Pick<
+  PublicSettings,
+  "post_edit_lock_hours" | "comment_edit_lock_hours" | "necro_reply_after_hours" | "necro_reply_penalty"
+>;
+type LockKey = keyof LockKeys;
+
+const LOCK_META: { key: LockKey; icon: React.ReactNode; label: string; hint: string; max: number; unit: string; toast: (v: number) => string }[] = [
+  {
+    key: "post_edit_lock_hours",
+    icon: <Lock size={15} />,
+    label: "帖子可编辑时长",
+    hint: "发帖后仅在该时长内可编辑（0=不限制，上限 8760 小时），到期后编辑入口隐藏；管理团队不受限。",
+    max: 8760,
+    unit: "小时",
+    toast: (v) => (v === 0 ? "已关闭帖子编辑时限" : `帖子可编辑时长已设为 ${v} 小时`),
+  },
+  {
+    key: "comment_edit_lock_hours",
+    icon: <Hourglass size={15} />,
+    label: "评论可编辑时长",
+    hint: "评论发布后仅在该时长内可编辑（0=不限制，上限 8760 小时）；管理团队不受限。",
+    max: 8760,
+    unit: "小时",
+    toast: (v) => (v === 0 ? "已关闭评论编辑时限" : `评论可编辑时长已设为 ${v} 小时`),
+  },
+  {
+    key: "necro_reply_after_hours",
+    icon: <History size={15} />,
+    label: "旧帖回复判定时长",
+    hint: "回复超过该时长的帖子将提醒作者并按下方分值扣分（0=关闭，上限 8760 小时）；管理团队不受限。",
+    max: 8760,
+    unit: "小时",
+    toast: (v) => (v === 0 ? "已关闭旧帖回复提醒" : `旧帖判定时长已设为 ${v} 小时`),
+  },
+  {
+    key: "necro_reply_penalty",
+    icon: <Coins size={15} />,
+    label: "旧帖回复扣除积分",
+    hint: "触发旧帖回复时扣除的积分（0=仅提醒不扣分，上限 100）；积分不足将无法回复。",
+    max: 100,
+    unit: "分",
+    toast: (v) => (v === 0 ? "旧帖回复仅提醒不扣分" : `旧帖回复将扣除 ${v} 积分`),
+  },
+];
+
+const pickLock = (s: PublicSettings): LockKeys => ({
+  post_edit_lock_hours: s.post_edit_lock_hours,
+  comment_edit_lock_hours: s.comment_edit_lock_hours,
+  necro_reply_after_hours: s.necro_reply_after_hours,
+  necro_reply_penalty: s.necro_reply_penalty,
+});
+
 /** 内容互动开关 + 访问安全模块 */
 export default function AccessSettings({ initial }: { initial: PublicSettings }) {
   const [allowComments, setAllowComments] = useState(initial.allow_comments !== false);
@@ -37,8 +90,12 @@ export default function AccessSettings({ initial }: { initial: PublicSettings })
   const [togglingTrust, setTogglingTrust] = useState(false);
   const [togglingWithoutReview, setTogglingWithoutReview] = useState(false);
   const [savingCooldown, setSavingCooldown] = useState(false);
+  const [lockForm, setLockForm] = useState<LockKeys>(() => pickLock(initial));
+  const [savedLock, setSavedLock] = useState<LockKeys>(() => pickLock(initial));
+  const [savingLockKey, setSavingLockKey] = useState<LockKey | null>(null);
   const [moduleDirty, setModuleDirty] = useState(false);
-  const leave = useUnsavedGuard(moduleDirty);
+  const lockDirty = (Object.keys(savedLock) as LockKey[]).some((k) => lockForm[k] !== savedLock[k]);
+  const leave = useUnsavedGuard(moduleDirty || lockDirty);
 
   const toggleComments = async () => {
     if (togglingComments) return;
@@ -164,6 +221,23 @@ export default function AccessSettings({ initial }: { initial: PublicSettings })
     }
   };
 
+  const saveLock = async (key: LockKey) => {
+    if (savingLockKey) return;
+    const n = Math.max(0, Math.min(8760, Math.round(Number(lockForm[key])) || 0));
+    setSavingLockKey(key);
+    try {
+      const res = await apiUpdateSiteSettings({ [key]: n });
+      const saved = pickLock(res);
+      setLockForm((f) => ({ ...f, [key]: saved[key] }));
+      setSavedLock((f) => ({ ...f, [key]: saved[key] }));
+      toast(LOCK_META.find((m) => m.key === key)?.toast(saved[key]) || "已保存", "ok");
+    } catch (e) {
+      toast(e instanceof Error ? e.message : "保存失败");
+    } finally {
+      setSavingLockKey(null);
+    }
+  };
+
   return (
     <div className="admin-settings-stack">
       <AdminSettingsGroup title="内容与互动">
@@ -308,6 +382,31 @@ export default function AccessSettings({ initial }: { initial: PublicSettings })
           </div>
         </AdminSettingsRow>
       </AdminSettingsGroup>
+      <AdminSettingsGroup title="内容锁定与旧帖回复">
+        {LOCK_META.map((m) => (
+          <AdminSettingsRow key={m.key} label={<span className="inline-flex items-center gap-1.5">{m.icon} {m.label}</span>} hintBelow={m.hint}>
+            <div className="flex items-center gap-2 flex-wrap">
+              <AdminStepper
+                value={lockForm[m.key]}
+                onChange={(v) => setLockForm((f) => ({ ...f, [m.key]: v }))}
+                min={0}
+                max={m.max}
+                unit={m.unit}
+                ariaLabel={`${m.label}${m.unit}`}
+                disabled={savingLockKey !== null}
+              />
+              <button
+                type="button"
+                className="btn btn-line btn-sm"
+                disabled={savingLockKey !== null || lockForm[m.key] === savedLock[m.key]}
+                onClick={() => void saveLock(m.key)}
+              >
+                {savingLockKey === m.key ? "保存中…" : "保存"}
+              </button>
+            </div>
+          </AdminSettingsRow>
+        ))}
+      </AdminSettingsGroup>
       <OperationsPanel name="security" onDirtyChange={setModuleDirty} />
       <ConfirmDialog
         open={leave.leaveOpen}

frontend/app/admin/settings/EconomySettings.tsx

@@ -212,7 +212,7 @@ export default function EconomySettings({ initial }: { initial: PublicSettings }
       <div className="flex items-center gap-3">
         <button
           type="button"
-          className="btn btn-solid btn-sm"
+          className="btn btn-primary btn-sm"
           disabled={saving || !dirty}
           onClick={() => void save()}
         >

frontend/app/globals.css

@@ -3335,6 +3335,12 @@ body:has([data-admin-viewport]) {
   padding-top: 0;
 }
 
+/* 用户积分表头吸顶：同 admin-users-stick，画布顶内边距必须归零 sticky 才能贴紧顶栏
+   （内边距挪到 .admin-points-users-tab；标记类仅在用户积分标签激活时挂载，不影响其他标签） */
+.admin-canvas:has(.admin-points-users-tab) {
+  padding-top: 0;
+}
+
 /* 移动端导航抽屉 */
 .admin-drawer {
   position: fixed;
@@ -5692,6 +5698,21 @@ a.j13-mention-token:hover {
     box-shadow: var(--shadow-sm);
   }
 
+  /* 用户积分标签：画布顶内边距挪到这里（见未分层区 canvas:has 规则），吸顶 th 才能贴齐 admin-topbar */
+  .admin-points-users-tab {
+    padding-top: 1.25rem;
+  }
+  @media (min-width: 640px) {
+    .admin-points-users-tab {
+      padding-top: 1.5rem;
+    }
+  }
+  @media (min-width: 1024px) {
+    .admin-points-users-tab {
+      padding-top: 1.75rem;
+    }
+  }
+
   /* 内容管理页：窄屏可整页滚；桌面高度由上方未分层的 canvas:has 规则锁定 */
   .admin-content-page {
     display: flex;
@@ -8409,6 +8430,78 @@ button.cmt-edited {
   text-decoration: underline;
   text-underline-offset: 2px;
 }
+/* 评论编辑历史：git diff 风格修订视图 */
+.cmt-diff {
+  display: flex;
+  flex-direction: column;
+  gap: 4px;
+}
+.cmt-diff-stat {
+  display: flex;
+  gap: 8px;
+  font-size: 11.5px;
+  font-weight: 600;
+  line-height: 1;
+  font-variant-numeric: tabular-nums;
+}
+.cmt-diff-stat-add {
+  color: var(--ok);
+}
+.cmt-diff-stat-del {
+  color: var(--danger);
+}
+.cmt-diff-body {
+  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
+  font-size: 12.5px;
+  line-height: 1.55;
+  background: var(--panel);
+  border: 1px solid var(--line);
+  border-radius: 6px;
+  padding: 4px 0;
+}
+.cmt-diff-line {
+  display: flex;
+  gap: 8px;
+  padding: 0 10px;
+  white-space: pre-wrap;
+  word-break: break-word;
+  min-height: 1.55em;
+}
+.cmt-diff-sign {
+  flex-shrink: 0;
+  width: 1ch;
+  user-select: none;
+  opacity: 0.65;
+}
+.cmt-diff-text {
+  min-width: 0;
+  flex: 1;
+}
+.cmt-diff-line.is-del {
+  background: color-mix(in srgb, var(--danger-soft) 60%, transparent);
+}
+.cmt-diff-line.is-add {
+  background: color-mix(in srgb, var(--ok-soft) 60%, transparent);
+}
+.cmt-diff-line.is-ctx {
+  color: var(--ink-2);
+}
+.cmt-diff-chg {
+  border-radius: 3px;
+  padding: 0 1px;
+  background: color-mix(in srgb, var(--danger) 24%, transparent);
+  color: inherit;
+}
+.cmt-diff-line.is-add .cmt-diff-chg {
+  background: color-mix(in srgb, var(--ok) 24%, transparent);
+}
+.cmt-diff-fold {
+  padding: 2px 10px;
+  font-size: 11.5px;
+  text-align: center;
+  color: var(--ink-2);
+  background: color-mix(in srgb, var(--ink) 3%, transparent);
+}
 .cmt-badge {
   display: inline-flex;
   align-items: center;

frontend/app/notifications/NotificationsClient.tsx

@@ -3,7 +3,7 @@
 import { useState } from "react";
 import { useRouter } from "next/navigation";
 import Link from "next/link";
-import { Heart, MessageCircle, CheckCheck, Bell, CheckCircle2, XCircle, AtSign, ClipboardList, Award } from "lucide-react";
+import { Heart, MessageCircle, CheckCheck, Bell, CheckCircle2, XCircle, AtSign, ClipboardList, Award, AlertTriangle } from "lucide-react";
 import { apiMarkRead, apiMarkAllRead, type NotificationsResponse, type NotificationItem } from "@/lib/api";
 
 /**
@@ -76,22 +76,26 @@ export default function NotificationsClient({ initialData }: { initialData: Noti
         <div className="panel overflow-hidden p-0">
           {notifications.map((n, i) => {
             const approval = n.type === "approved" || n.type === "rejected";
+            // 系统提醒（ActorID=0）：不渲染操作者链接，仅展示标题与内容
+            const system = n.type === "necro_reply";
             const iconNode = n.type === "approved"
               ? <CheckCircle2 size={16} />
               : n.type === "rejected" || n.type === "deleted"
                 ? <XCircle size={16} />
-                : n.type === "like"
-                  ? <Heart size={16} />
-                  : n.type === "mention"
-                    ? <AtSign size={16} />
-                    : n.type === "pending_review"
-                      ? <ClipboardList size={16} />
-                      : n.type === "badge"
-                        ? <Award size={16} />
-                        : <MessageCircle size={16} />;
+                : n.type === "necro_reply"
+                  ? <AlertTriangle size={16} />
+                  : n.type === "like"
+                    ? <Heart size={16} />
+                    : n.type === "mention"
+                      ? <AtSign size={16} />
+                      : n.type === "pending_review"
+                        ? <ClipboardList size={16} />
+                        : n.type === "badge"
+                          ? <Award size={16} />
+                          : <MessageCircle size={16} />;
             const iconColor = n.type === "approved"
               ? "var(--ok)"
-              : n.type === "rejected" || n.type === "deleted"
+              : n.type === "rejected" || n.type === "deleted" || n.type === "necro_reply"
                 ? "var(--danger)"
                 : n.type === "like"
                   ? "var(--clay)"
@@ -100,7 +104,7 @@ export default function NotificationsClient({ initialData }: { initialData: Noti
                     : "var(--accent)";
             const iconBg = n.type === "approved"
               ? "var(--ok-soft)"
-              : n.type === "rejected" || n.type === "deleted"
+              : n.type === "rejected" || n.type === "deleted" || n.type === "necro_reply"
                 ? "var(--danger-soft)"
                 : n.type === "like"
                   ? "var(--clay-soft)"
@@ -133,6 +137,10 @@ export default function NotificationsClient({ initialData }: { initialData: Noti
                     >
                       {n.type === "approved" ? "审核通过" : "未通过审核"}
                     </span>
+                  ) : system ? (
+                    <span className="font-bold" style={{ color: "var(--danger)" }}>
+                      旧帖回复提醒
+                    </span>
                   ) : (
                     <>
                       <Link

frontend/app/post/[id]/page.tsx

@@ -37,6 +37,7 @@ import BadgeChip from "@/components/BadgeChip";
 import MarkdownBody from "@/components/MarkdownBody";
 import { publicMarkdownForSeo } from "@/lib/hideBlocks";
 import PostAttachments from "@/components/PostAttachments";
+import PostEditedMark from "@/components/PostEditedMark";
 import PostInteractPanels, { QuestionStatusCard } from "@/components/PostInteractPanels";
 import AcceptedAnswerCard from "@/components/AcceptedAnswerCard";
 import { canModerateBoard } from "@/lib/roles";
@@ -323,8 +324,7 @@ export default async function PostDetailPage({ params, searchParams }: PageProps
   const toc = extractToc(publicBody);
   const headingToc = markdownHeadingToc(toc);
   const readingMinutes = estimateReadingMinutes(publicBody, post.title.length);
-  const edited =
-    new Date(post.updated_at).getTime() - new Date(post.created_at).getTime() > 60_000;
+  const edited = post.edited ?? false;
 
   // 侧栏布局：post 范围左右两列（toc 需在下方已就绪）
   const sidebarLists = sidebarScopeLists(sidebar.config, "post");
@@ -560,6 +560,9 @@ export default async function PostDetailPage({ params, searchParams }: PageProps
                     pinned={post.pinned}
                     recommended={post.recommended}
                     status={post.status}
+                    createdAt={post.created_at}
+                    locked={post.locked}
+                    postEditLockHours={publicSettings.post_edit_lock_hours}
                     title={post.title}
                   />
                 </div>
@@ -586,6 +589,16 @@ export default async function PostDetailPage({ params, searchParams }: PageProps
                       <>
                         {" "}
                         · 更新于 <time dateTime={post.updated_at}>{formatDateTime(post.updated_at)}</time>
+                        {me.user && (
+                          <>
+                            {" "}·{" "}
+                            <PostEditedMark
+                              postId={post.id}
+                              currentTitle={post.title}
+                              currentContent={post.content || ""}
+                            />
+                          </>
+                        )}
                       </>
                     )}
                   </p>
@@ -670,6 +683,9 @@ export default async function PostDetailPage({ params, searchParams }: PageProps
                 page={commentsData.page}
                 size={commentsData.size}
                 user={me.user}
+                postLocked={post.locked}
+                commentEditLockHours={publicSettings.comment_edit_lock_hours}
+                necroReply={post.necro_reply}
                 acceptMode={acceptMode}
                 acceptedCommentId={
                   post.question?.accepted_comment_id ||

frontend/components/CommentEditHistoryModal.tsx

@@ -1,173 +0,0 @@
-"use client";
-
-import { useCallback, useEffect, useState } from "react";
-import Link from "next/link";
-import { Loader2 } from "lucide-react";
-import Modal from "@/components/Modal";
-import Avatar from "@/components/Avatar";
-import MarkdownBodyClient from "@/components/MarkdownBodyClient";
-import {
-  apiAdminCommentHistory,
-  type CommentEditHistoryItem,
-} from "@/lib/api";
-
-const PAGE_SIZE = 10;
-
-/**
- * 版主可见：评论历次编辑前的旧正文快照（倒序分页）。
- * 宽度对齐详情页评论主栏（约 800px+），长文可滚动；底部「加载更多」。
- */
-export default function CommentEditHistoryModal({
-  open,
-  commentId,
-  onClose,
-}: {
-  open: boolean;
-  commentId: number | null;
-  onClose: () => void;
-}) {
-  const [loading, setLoading] = useState(false);
-  const [loadingMore, setLoadingMore] = useState(false);
-  const [error, setError] = useState("");
-  const [items, setItems] = useState<CommentEditHistoryItem[]>([]);
-  const [page, setPage] = useState(1);
-  const [total, setTotal] = useState(0);
-
-  const hasMore = items.length < total;
-
-  const loadPage = useCallback(
-    async (nextPage: number, append: boolean) => {
-      if (commentId == null) return;
-      if (append) setLoadingMore(true);
-      else {
-        setLoading(true);
-        setError("");
-      }
-      try {
-        const res = await apiAdminCommentHistory(commentId, nextPage, PAGE_SIZE);
-        const batch = res.items || [];
-        setError("");
-        setTotal(res.total ?? 0);
-        setPage(res.page ?? nextPage);
-        setItems((prev) => (append ? [...prev, ...batch] : batch));
-      } catch (e) {
-        const msg = e instanceof Error ? e.message : "加载失败";
-        if (append) {
-          // 追加失败不清空已有列表
-          setError(msg);
-        } else {
-          setError(msg);
-          setItems([]);
-          setTotal(0);
-        }
-      } finally {
-        setLoading(false);
-        setLoadingMore(false);
-      }
-    },
-    [commentId]
-  );
-
-  useEffect(() => {
-    if (!open || commentId == null) return;
-    setItems([]);
-    setPage(1);
-    setTotal(0);
-    setError("");
-    void loadPage(1, false);
-  }, [open, commentId, loadPage]);
-
-  return (
-    <Modal
-      open={open}
-      title="评论编辑历史"
-      description={total > 0 ? `共 ${total} 条修订记录` : undefined}
-      onClose={onClose}
-      // 对齐详情页中间评论栏可用宽度（1440 三栏布局下约 800px）
-      maxWidthClass="max-w-[min(840px,calc(100vw-2rem))]"
-      panelClassName="p-5 sm:p-6 max-h-[85vh] flex flex-col min-h-0 overflow-hidden"
-      bodyClassName="overflow-y-auto min-h-0 flex-1 -mx-1 px-1"
-      footer={
-        <button type="button" className="btn btn-line btn-sm" onClick={onClose}>
-          关闭
-        </button>
-      }
-    >
-      {loading ? (
-        <div className="flex items-center justify-center gap-2 py-10 meta text-[13px]">
-          <Loader2 size={16} className="animate-spin" />
-          加载中…
-        </div>
-      ) : error && items.length === 0 ? (
-        <p className="text-[13.5px] py-6 text-center" style={{ color: "var(--danger)" }}>
-          {error}
-        </p>
-      ) : items.length === 0 ? (
-        <p className="meta text-[13.5px] py-8 text-center">暂无编辑记录</p>
-      ) : (
-        <div className="flex flex-col gap-4">
-          <ul className="flex flex-col gap-4">
-            {items.map((it) => {
-              const name = it.editor.nickname || it.editor.username || "用户";
-              return (
-                <li
-                  key={it.id}
-                  className="rounded-md p-3 sm:p-4"
-                  style={{ background: "var(--panel-2)", border: "1px solid var(--line)" }}
-                >
-                  <div className="flex items-center gap-2 mb-2.5">
-                    <Link href={`/u/${it.editor.id}`} className="shrink-0">
-                      <Avatar name={name} src={it.editor.avatar || undefined} size={28} />
-                    </Link>
-                    <div className="min-w-0 flex-1">
-                      <Link
-                        href={`/u/${it.editor.id}`}
-                        className="text-[13px] hover:text-[var(--accent)]"
-                        style={{ color: "var(--ink)" }}
-                      >
-                        {name}
-                      </Link>
-                      <p className="meta text-[11.5px] tabular-nums">
-                        {new Date(it.created_at).toLocaleString("zh-CN")} · 编辑前正文
-                      </p>
-                    </div>
-                  </div>
-                  <MarkdownBodyClient
-                    content={it.old_content}
-                    className="prose-content prose-comment"
-                  />
-                </li>
-              );
-            })}
-          </ul>
-
-          {error && items.length > 0 && (
-            <p className="text-[12.5px] text-center" style={{ color: "var(--danger)" }}>
-              {error}
-            </p>
-          )}
-
-          {hasMore && (
-            <div className="flex justify-center pt-1 pb-1">
-              <button
-                type="button"
-                className="btn btn-line btn-sm"
-                disabled={loadingMore}
-                onClick={() => void loadPage(page + 1, true)}
-              >
-                {loadingMore ? (
-                  <span className="inline-flex items-center gap-1.5">
-                    <Loader2 size={14} className="animate-spin" />
-                    加载中…
-                  </span>
-                ) : (
-                  `加载更多（已显示 ${items.length}/${total}）`
-                )}
-              </button>
-            </div>
-          )}
-        </div>
-      )}
-    </Modal>
-  );
-}

frontend/components/CommentSection.tsx

@@ -1,4 +1,4 @@
-"use client";
+"use client";
 
 import { useEffect, useRef, useState } from "react";
 import { useRouter } from "next/navigation";
@@ -7,6 +7,7 @@ import {
   MessagesSquare,
   ChevronRight,
   ChevronDown,
+  Lock,
 } from "lucide-react";
 import {
   apiCreateComment,
@@ -16,13 +17,14 @@ import {
   apiUpdateComment,
   apiAcceptBounty,
   apiAcceptQuestion,
+  apiCommentHistory,
   apiAdminApproveComment,
   apiAdminRejectComment,
   postDeleteTypeLabel,
   type CommentNode,
   type User,
 } from "@/lib/api";
-import { canModerateBoard, canStaffSoftDelete, canPurgeContent } from "@/lib/roles";
+import { canModerateBoard, canStaffSoftDelete, canPurgeContent, isStaff } from "@/lib/roles";
 import { toast } from "@/lib/toast";
 import { formatCommentTime, formatDateTime } from "@/lib/format";
 import { useAllowComments, useCommentsRequireLogin } from "@/components/CommentsPolicyProvider";
@@ -36,7 +38,7 @@ import MarkdownBodyClient from "@/components/MarkdownBodyClient";
 import MarkdownEditor from "@/components/MarkdownEditor";
 import ConfirmDialog from "@/components/ConfirmDialog";
 import DeleteCommentModal, { type DeleteCommentPayload } from "@/components/DeleteCommentModal";
-import CommentEditHistoryModal from "@/components/CommentEditHistoryModal";
+import EditHistoryModal from "@/components/EditHistoryModal";
 
 interface CommentSectionProps {
   postId: string;
@@ -56,6 +58,12 @@ interface CommentSectionProps {
   acceptedCommentId?: number;
   /** 抽奖已开奖：中奖楼层评论 ID（每名中奖者仅其最早主评一条） */
   winnerCommentIds?: number[];
+  /** 帖子是否被管理员手动锁定（普通用户不可回复/编辑评论，staff 豁免） */
+  postLocked: boolean;
+  /** 评论可编辑时长（小时）；0=不锁定；staff 豁免 */
+  commentEditLockHours: number;
+  /** 旧帖回复确认提示（后端按查看者计算；存在时提交回复前需用户确认，确认后发送并扣分） */
+  necroReply?: { after_hours: number; penalty: number } | null;
 }
 
 // 递归统计子树回复数（彻底删除级联提示用）
@@ -63,6 +71,9 @@ function countReplies(node: CommentNode): number {
   return node.replies?.reduce((acc, r) => acc + 1 + countReplies(r), 0) ?? 0;
 }
 
+/** 评论正文字符上限（与后端 handler/comment.go 校验一致） */
+const COMMENT_MAX = 5000;
+
 function findComment(nodes: CommentNode[], id: number): CommentNode | null {
   for (const n of nodes) {
     if (n.id === id) return n;
@@ -196,11 +207,22 @@ export default function CommentSection({
   acceptMode = null,
   acceptedCommentId = 0,
   winnerCommentIds = [],
+  postLocked,
+  commentEditLockHours,
+  necroReply = null,
 }: CommentSectionProps) {
   const winnerCommentIdSet = new Set(winnerCommentIds.filter((id) => id > 0));
   const router = useRouter();
   const commentsOpen = useAllowComments();
   const commentsRequireLogin = useCommentsRequireLogin();
+  const staffViewer = !!user && isStaff(user.role);
+  /** 锁帖后普通用户禁止回复与编辑自己的评论，staff 豁免 */
+  const replyBlocked = postLocked && !staffViewer;
+  /** 评论是否已超过可编辑时限（staff 豁免；0=不启用） */
+  const commentTimeLocked = (createdAt: string) =>
+    !staffViewer &&
+    commentEditLockHours > 0 &&
+    Date.now() - new Date(createdAt).getTime() > commentEditLockHours * 3_600_000;
   const [content, setContent] = useState("");
   // 内联回复目标：同一时间只有一个回复框；草稿按目标评论隔离
   const [replyTarget, setReplyTarget] = useState<{
@@ -221,6 +243,8 @@ export default function CommentSection({
   const [replyUploading, setReplyUploading] = useState(false);
   const [editUploading, setEditUploading] = useState(false);
   const [awayHref, setAwayHref] = useState<string | null>(null);
+  // 旧帖回复确认：记录待确认的提交入口（主楼层 / 内联回复）
+  const [necroConfirm, setNecroConfirm] = useState<null | "floor" | "reply">(null);
   const [discardReplyOpen, setDiscardReplyOpen] = useState(false);
   const [discardEditOpen, setDiscardEditOpen] = useState(false);
   const [deleting, setDeleting] = useState(false);
@@ -237,6 +261,7 @@ export default function CommentSection({
   const [editContent, setEditContent] = useState("");
   const [savingEdit, setSavingEdit] = useState(false);
   const [historyCommentId, setHistoryCommentId] = useState<number | null>(null);
+  const [historyCommentContent, setHistoryCommentContent] = useState("");
   // 折叠状态：哪些楼层展开了子回复（默认全部折叠，SSR 初始为收起）
   const [expandedFloors, setExpandedFloors] = useState<Set<number>>(new Set());
 
@@ -304,6 +329,11 @@ export default function CommentSection({
 
   const handleSubmit = (e: React.FormEvent) => {
     e.preventDefault();
+    // 旧帖回复：确认后才发送并扣分（后端按查看者下发提示，staff/待审用户不会拿到）
+    if (necroReply) {
+      setNecroConfirm("floor");
+      return;
+    }
     void submitFloor();
   };
 
@@ -347,6 +377,11 @@ export default function CommentSection({
 
   const handleSubmitReply = (e: React.FormEvent) => {
     e.preventDefault();
+    // 旧帖回复：确认后才发送并扣分
+    if (necroReply) {
+      setNecroConfirm("reply");
+      return;
+    }
     void submitReply();
   };
 
@@ -472,9 +507,16 @@ export default function CommentSection({
     (user.id === comment.user?.id ||
       canStaffSoftDelete(user, boardId, comment.user?.role));
 
-  const canEdit = (comment: CommentNode) => canSoftDelete(comment);
+  const canEdit = (comment: CommentNode) => {
+    if (!canSoftDelete(comment)) return false;
+    // 作者本人编辑：锁帖与可编辑时限限制（staff 豁免；版主编辑他人不受此限）
+    if (user?.id === comment.user?.id && (replyBlocked || commentTimeLocked(comment.created_at))) {
+      return false;
+    }
+    return true;
+  };
 
-  const canViewHistory = !!user && canModerateBoard(user, boardId);
+  const canViewHistory = !!user;
 
   const canPurge = (comment: CommentNode) =>
     !!user && canPurgeContent(user.role) && canModerateBoard(user, boardId);
@@ -615,9 +657,10 @@ export default function CommentSection({
             density="comment"
             value={editContent}
             onChange={(v) => {
-              setEditContent(v);
+              setEditContent(v.slice(0, COMMENT_MAX));
               if (editError) setEditError("");
             }}
+            maxChars={COMMENT_MAX}
             disabled={savingEdit}
             autoFocus
             allowHide={false}
@@ -671,7 +714,14 @@ export default function CommentSection({
     if (!c.edited) return null;
     if (canViewHistory) {
       return (
-        <button type="button" className="cmt-edited" onClick={() => setHistoryCommentId(c.id)}>
+        <button
+          type="button"
+          className="cmt-edited"
+          onClick={() => {
+            setHistoryCommentContent(c.content);
+            setHistoryCommentId(c.id);
+          }}
+        >
           已编辑
         </button>
       );
@@ -693,11 +743,15 @@ export default function CommentSection({
         onSelect: () => startEdit(c),
       });
     }
-    if (canViewHistory) {
+    // 未编辑（无修订快照）的评论不展示历史入口，避免打开空记录
+    if (canViewHistory && c.edited) {
       items.push({
         key: "history",
         label: "编辑历史",
-        onSelect: () => setHistoryCommentId(c.id),
+        onSelect: () => {
+          setHistoryCommentContent(c.content);
+          setHistoryCommentId(c.id);
+        },
       });
     }
     if (canRestore(c)) {
@@ -758,9 +812,10 @@ export default function CommentSection({
           density="comment"
           value={replyContent}
           onChange={(v) => {
-            setReplyContent(v);
+            setReplyContent(v.slice(0, COMMENT_MAX));
             if (replyError) setReplyError("");
           }}
+          maxChars={COMMENT_MAX}
           disabled={submitting}
           autoFocus
           allowHide={false}
@@ -1015,7 +1070,7 @@ export default function CommentSection({
               </div>
               {renderContentOrEditor(c)}
               <div className="cmt-actions">
-                {commentsOpen && user && editingId !== c.id && (
+                {commentsOpen && user && !replyBlocked && editingId !== c.id && (
                   <button
                     type="button"
                     onClick={() => openReply(c, floor)}
@@ -1117,7 +1172,7 @@ export default function CommentSection({
             </div>
             {renderContentOrEditor(c)}
             <div className="cmt-actions">
-              {commentsOpen && user && editingId !== c.id && (
+              {commentsOpen && user && !replyBlocked && editingId !== c.id && (
                 <button
                   type="button"
                   onClick={() => openReply(c, floor)}
@@ -1214,7 +1269,18 @@ export default function CommentSection({
         ) : null}
       </div>
 
-      {user ? (
+      {replyBlocked ? (
+        <div
+          className="mb-8 px-5 py-4 rounded-2xl flex items-center gap-2.5 border"
+          style={{ borderColor: "var(--line)", background: "transparent" }}
+          role="status"
+        >
+          <Lock size={15} style={{ color: "var(--ink-3)" }} className="shrink-0" />
+          <span className="text-sm" style={{ color: "var(--ink-2)" }}>
+            帖子已被锁定，暂时无法回复
+          </span>
+        </div>
+      ) : user ? (
         <form onSubmit={handleSubmit} className="mb-6">
           <div className="cmt-md-editor cmt-md-editor-floor scroll-mt-28">
             <MarkdownEditor
@@ -1222,9 +1288,10 @@ export default function CommentSection({
               density="comment"
               value={content}
               onChange={(v) => {
-                setContent(v);
+                setContent(v.slice(0, COMMENT_MAX));
                 if (floorError) setFloorError("");
               }}
+              maxChars={COMMENT_MAX}
               disabled={submitting}
               allowHide={false}
               ariaLabel="发表评论"
@@ -1355,9 +1422,29 @@ export default function CommentSection({
         onCancel={() => setDiscardEditOpen(false)}
       />
 
-      <CommentEditHistoryModal
+      {/* 旧帖回复确认：确认后才发送并扣分（提示由后端按查看者下发） */}
+      <ConfirmDialog
+        open={necroConfirm !== null}
+        title="回复旧帖提醒"
+        message={`该帖已超过 ${necroReply?.after_hours ?? 0} 小时没有新回复，回复将扣除 ${necroReply?.penalty ?? 0} 积分。确定继续吗？`}
+        confirmLabel="继续回复"
+        onConfirm={() => {
+          const kind = necroConfirm;
+          setNecroConfirm(null);
+          if (kind === "floor") void submitFloor();
+          else if (kind === "reply") void submitReply();
+        }}
+        onCancel={() => setNecroConfirm(null)}
+      />
+
+      <EditHistoryModal
         open={historyCommentId != null}
-        commentId={historyCommentId}
+        title="评论编辑历史"
+        currentContent={historyCommentContent}
+        fetchPage={(p, s) => {
+          if (historyCommentId == null) return Promise.reject(new Error("未选择评论"));
+          return apiCommentHistory(historyCommentId, p, s);
+        }}
         onClose={() => setHistoryCommentId(null)}
       />
     </section>

frontend/components/EditHistoryModal.tsx

@@ -0,0 +1,433 @@
+"use client";
+
+import { useCallback, useEffect, useMemo, useState } from "react";
+import Link from "next/link";
+import { Loader2 } from "lucide-react";
+import Modal from "@/components/Modal";
+import Avatar from "@/components/Avatar";
+
+const PAGE_SIZE = 10;
+
+export interface EditHistoryItem {
+  id: number;
+  editor: {
+    id: number;
+    username: string;
+    nickname: string;
+    avatar: string;
+  };
+  old_title?: string; // 帖子场景有；评论场景无
+  old_content: string;
+  created_at: string;
+}
+
+export type FetchHistoryPage = (
+  page: number,
+  size: number
+) => Promise<{
+  items: EditHistoryItem[];
+  total: number;
+  page: number;
+  size: number;
+}>;
+
+/* ---------------- 行级 diff（LCS），git diff 风格渲染 ---------------- */
+
+type DiffOp = "del" | "add" | "ctx";
+
+interface DiffLine {
+  op: DiffOp;
+  text: string;
+}
+
+interface Seg {
+  chg: boolean;
+  text: string;
+}
+
+type Row =
+  | { kind: "line"; op: DiffOp; text: string; pair: string | null }
+  | { kind: "fold"; count: number };
+
+// 超大文本退化为整段替换，避免 O(n·m) 内存膨胀
+const MAX_DIFF_CELLS = 400_000;
+// 单行超过该长度不做行内变更高亮
+const MAX_INLINE_DIFF_LEN = 2000;
+// 相同内容行超过该数量时折叠中段
+const CONTEXT_FOLD_LIMIT = 8;
+
+function splitLines(text: string): string[] {
+  if (!text) return [];
+  return text.replace(/\r\n/g, "\n").split("\n");
+}
+
+function diffLines(oldText: string, newText: string): DiffLine[] {
+  const a = splitLines(oldText);
+  const b = splitLines(newText);
+  const n = a.length;
+  const m = b.length;
+  if (n * m > MAX_DIFF_CELLS) {
+    return [
+      ...a.map((text) => ({ op: "del" as const, text })),
+      ...b.map((text) => ({ op: "add" as const, text })),
+    ];
+  }
+  const width = m + 1;
+  const dp = new Uint32Array((n + 1) * width);
+  for (let i = n - 1; i >= 0; i--) {
+    for (let j = m - 1; j >= 0; j--) {
+      dp[i * width + j] =
+        a[i] === b[j]
+          ? dp[(i + 1) * width + (j + 1)] + 1
+          : Math.max(dp[(i + 1) * width + j], dp[i * width + (j + 1)]);
+    }
+  }
+  const out: DiffLine[] = [];
+  let i = 0;
+  let j = 0;
+  while (i < n && j < m) {
+    if (a[i] === b[j]) {
+      out.push({ op: "ctx", text: a[i] });
+      i += 1;
+      j += 1;
+    } else if (dp[(i + 1) * width + j] >= dp[i * width + (j + 1)]) {
+      out.push({ op: "del", text: a[i] });
+      i += 1;
+    } else {
+      out.push({ op: "add", text: b[j] });
+      j += 1;
+    }
+  }
+  while (i < n) {
+    out.push({ op: "del", text: a[i] });
+    i += 1;
+  }
+  while (j < m) {
+    out.push({ op: "add", text: b[j] });
+    j += 1;
+  }
+  return normalizeBlocks(out);
+}
+
+// 每个连续变更块内统一「先删后增」，与 git diff 呈现一致
+function normalizeBlocks(lines: DiffLine[]): DiffLine[] {
+  const out: DiffLine[] = [];
+  let k = 0;
+  while (k < lines.length) {
+    if (lines[k].op === "ctx") {
+      out.push(lines[k]);
+      k += 1;
+      continue;
+    }
+    let end = k;
+    while (end < lines.length && lines[end].op !== "ctx") end += 1;
+    for (let t = k; t < end; t++) if (lines[t].op === "del") out.push(lines[t]);
+    for (let t = k; t < end; t++) if (lines[t].op === "add") out.push(lines[t]);
+    k = end;
+  }
+  return out;
+}
+
+// 行内变更高亮：取公共前/后缀，中间差异段标记 chg
+function segmentLine(line: string, other: string | null): Seg[] {
+  if (
+    !other ||
+    line === other ||
+    line.length + other.length > MAX_INLINE_DIFF_LEN * 2
+  ) {
+    return [{ chg: false, text: line }];
+  }
+  const min = Math.min(line.length, other.length);
+  let p = 0;
+  while (p < min && line[p] === other[p]) p += 1;
+  let s = 0;
+  while (
+    s < min - p &&
+    line[line.length - 1 - s] === other[other.length - 1 - s]
+  ) {
+    s += 1;
+  }
+  const segs: Seg[] = [];
+  if (p > 0) segs.push({ chg: false, text: line.slice(0, p) });
+  const mid = line.slice(p, line.length - s);
+  if (mid) segs.push({ chg: true, text: mid });
+  if (s > 0) segs.push({ chg: false, text: line.slice(line.length - s) });
+  return segs.length > 0 ? segs : [{ chg: false, text: line }];
+}
+
+// 折叠长段相同内容；同块内删除/新增按序号配对做行内高亮
+function buildRows(lines: DiffLine[]): Row[] {
+  const rows: Row[] = [];
+  let k = 0;
+  while (k < lines.length) {
+    if (lines[k].op === "ctx") {
+      let end = k;
+      while (end < lines.length && lines[end].op === "ctx") end += 1;
+      const run = end - k;
+      if (run > CONTEXT_FOLD_LIMIT) {
+        for (let t = k; t < k + 3; t++) {
+          rows.push({ kind: "line", op: lines[t].op, text: lines[t].text, pair: null });
+        }
+        rows.push({ kind: "fold", count: run - 6 });
+        for (let t = end - 3; t < end; t++) {
+          rows.push({ kind: "line", op: lines[t].op, text: lines[t].text, pair: null });
+        }
+      } else {
+        for (let t = k; t < end; t++) {
+          rows.push({ kind: "line", op: lines[t].op, text: lines[t].text, pair: null });
+        }
+      }
+      k = end;
+    } else {
+      let end = k;
+      while (end < lines.length && lines[end].op !== "ctx") end += 1;
+      const dels = lines.slice(k, end).filter((l) => l.op === "del");
+      const adds = lines.slice(k, end).filter((l) => l.op === "add");
+      const pairFor = new Map<DiffLine, string | null>();
+      const cnt = Math.min(dels.length, adds.length);
+      for (let t = 0; t < cnt; t++) {
+        pairFor.set(dels[t], adds[t].text);
+        pairFor.set(adds[t], dels[t].text);
+      }
+      for (let t = k; t < end; t++) {
+        rows.push({
+          kind: "line",
+          op: lines[t].op,
+          text: lines[t].text,
+          pair: pairFor.get(lines[t]) ?? null,
+        });
+      }
+      k = end;
+    }
+  }
+  return rows;
+}
+
+function DiffBody({ before, after }: { before: string; after: string }) {
+  const rows = useMemo(() => buildRows(diffLines(before, after)), [before, after]);
+  const delCount = rows.filter((r) => r.kind === "line" && r.op === "del").length;
+  const addCount = rows.filter((r) => r.kind === "line" && r.op === "add").length;
+  return (
+    <div className="cmt-diff">
+      <div className="cmt-diff-stat">
+        <span className="cmt-diff-stat-add">+{addCount}</span>
+        <span className="cmt-diff-stat-del">−{delCount}</span>
+      </div>
+      <div className="cmt-diff-body">
+        {rows.map((r, idx) =>
+          r.kind === "fold" ? (
+            <div key={idx} className="cmt-diff-fold">
+              ⋯ 已省略 {r.count} 行相同内容 ⋯
+            </div>
+          ) : (
+            <div key={idx} className={`cmt-diff-line is-${r.op}`}>
+              <span className="cmt-diff-sign" aria-hidden>
+                {r.op === "del" ? "-" : r.op === "add" ? "+" : " "}
+              </span>
+              <span className="cmt-diff-text">
+                {segmentLine(r.text, r.pair).map((s, si) =>
+                  s.chg ? (
+                    <mark key={si} className="cmt-diff-chg">
+                      {s.text}
+                    </mark>
+                  ) : (
+                    <span key={si}>{s.text}</span>
+                  )
+                )}
+              </span>
+            </div>
+          )
+        )}
+      </div>
+    </div>
+  );
+}
+
+/* ---------------- 弹窗 ---------------- */
+
+/**
+ * 登录可见：历次编辑的 git diff 风格修订视图（倒序分页）。
+ * 后端只存每次编辑前的旧快照：第 i 条的「改后内容」= 第 i-1 条（更新的一条）的快照，
+ * 最新一条的「改后内容」= 当前正文（由调用方传入）。帖子场景另传 currentTitle 渲染标题 diff。
+ */
+export default function EditHistoryModal({
+  open,
+  title,
+  currentTitle,
+  currentContent,
+  fetchPage,
+  onClose,
+}: {
+  open: boolean;
+  title: string;
+  currentTitle?: string;
+  currentContent: string;
+  fetchPage: FetchHistoryPage;
+  onClose: () => void;
+}) {
+  const [loading, setLoading] = useState(false);
+  const [loadingMore, setLoadingMore] = useState(false);
+  const [error, setError] = useState("");
+  const [items, setItems] = useState<EditHistoryItem[]>([]);
+  const [page, setPage] = useState(1);
+  const [total, setTotal] = useState(0);
+
+  const hasMore = items.length < total;
+
+  const loadPage = useCallback(
+    async (nextPage: number, append: boolean) => {
+      if (!open) return;
+      if (append) setLoadingMore(true);
+      else {
+        setLoading(true);
+        setError("");
+      }
+      try {
+        const res = await fetchPage(nextPage, PAGE_SIZE);
+        const batch = res.items || [];
+        setError("");
+        setTotal(res.total ?? 0);
+        setPage(res.page ?? nextPage);
+        setItems((prev) => (append ? [...prev, ...batch] : batch));
+      } catch (e) {
+        const msg = e instanceof Error ? e.message : "加载失败";
+        if (append) {
+          // 追加失败不清空已有列表
+          setError(msg);
+        } else {
+          setError(msg);
+          setItems([]);
+          setTotal(0);
+        }
+      } finally {
+        setLoading(false);
+        setLoadingMore(false);
+      }
+    },
+    [open, fetchPage]
+  );
+
+  useEffect(() => {
+    if (!open) return;
+    setItems([]);
+    setPage(1);
+    setTotal(0);
+    setError("");
+    void loadPage(1, false);
+  }, [open, loadPage]);
+
+  const hasTitle = typeof currentTitle === "string";
+
+  return (
+    <Modal
+      open={open}
+      title={title}
+      description={total > 0 ? `共 ${total} 条修订记录 · - 移除内容 / + 新增内容` : undefined}
+      onClose={onClose}
+      // 对齐详情页中间评论栏可用宽度（1440 三栏布局下约 800px）
+      maxWidthClass="max-w-[min(840px,calc(100vw-2rem))]"
+      panelClassName="p-5 sm:p-6 max-h-[85vh] flex flex-col min-h-0 overflow-hidden"
+      bodyClassName="overflow-y-auto min-h-0 flex-1 -mx-1 px-1"
+      footer={
+        <button type="button" className="btn btn-line btn-sm" onClick={onClose}>
+          关闭
+        </button>
+      }
+    >
+      {loading ? (
+        <div className="flex items-center justify-center gap-2 py-10 meta text-[13px]">
+          <Loader2 size={16} className="animate-spin" />
+          加载中…
+        </div>
+      ) : error && items.length === 0 ? (
+        <p className="text-[13.5px] py-6 text-center" style={{ color: "var(--danger)" }}>
+          {error}
+        </p>
+      ) : items.length === 0 ? (
+        <p className="meta text-[13.5px] py-8 text-center">暂无编辑记录</p>
+      ) : (
+        <div className="flex flex-col gap-4">
+          <ul className="flex flex-col gap-4">
+            {items.map((it, idx) => {
+              const name = it.editor.nickname || it.editor.username || "用户";
+              // 本次编辑的改后内容：上一条（更新的）快照；最新一条为当前正文
+              const afterContent = idx === 0 ? currentContent : items[idx - 1].old_content;
+              const afterTitle = hasTitle
+                ? idx === 0
+                  ? (currentTitle ?? "")
+                  : (items[idx - 1].old_title ?? "")
+                : undefined;
+              const titleChanged = hasTitle && it.old_title !== afterTitle;
+              const contentChanged = it.old_content !== afterContent;
+              return (
+                <li
+                  key={it.id}
+                  className="rounded-md p-3 sm:p-4"
+                  style={{ background: "var(--panel-2)", border: "1px solid var(--line)" }}
+                >
+                  <div className="flex items-center gap-2 mb-2.5">
+                    <Link href={`/u/${it.editor.id}`} className="shrink-0">
+                      <Avatar name={name} src={it.editor.avatar || undefined} size={28} />
+                    </Link>
+                    <div className="min-w-0 flex-1">
+                      <Link
+                        href={`/u/${it.editor.id}`}
+                        className="text-[13px] hover:text-[var(--accent)]"
+                        style={{ color: "var(--ink)" }}
+                      >
+                        {name}
+                      </Link>
+                      <p className="meta text-[11.5px] tabular-nums">
+                        {new Date(it.created_at).toLocaleString("zh-CN")} · 第{" "}
+                        {total - idx} 次编辑
+                      </p>
+                    </div>
+                  </div>
+                  {titleChanged && (
+                    <div className="mb-3">
+                      <p className="meta text-[11.5px] mb-1">标题</p>
+                      <DiffBody before={it.old_title ?? ""} after={afterTitle ?? ""} />
+                    </div>
+                  )}
+                  {contentChanged ? (
+                    <DiffBody before={it.old_content} after={afterContent} />
+                  ) : (
+                    !titleChanged && (
+                      <p className="meta text-[12.5px]">本次仅变更了标签或其他元数据，未修改标题/正文。</p>
+                    )
+                  )}
+                </li>
+              );
+            })}
+          </ul>
+
+          {error && items.length > 0 && (
+            <p className="text-[12.5px] text-center" style={{ color: "var(--danger)" }}>
+              {error}
+            </p>
+          )}
+
+          {hasMore && (
+            <div className="flex justify-center pt-1 pb-1">
+              <button
+                type="button"
+                className="btn btn-line btn-sm"
+                disabled={loadingMore}
+                onClick={() => void loadPage(page + 1, true)}
+              >
+                {loadingMore ? (
+                  <span className="inline-flex items-center gap-1.5">
+                    <Loader2 size={14} className="animate-spin" />
+                    加载中…
+                  </span>
+                ) : (
+                  `加载更多（已显示 ${items.length}/${total}）`
+                )}
+              </button>
+            </div>
+          )}
+        </div>
+      )}
+    </Modal>
+  );
+}

frontend/components/MarkdownEditor.tsx

@@ -71,6 +71,8 @@ type MarkdownEditorProps = {
   shortcutName?: string;
   /** 底栏右侧操作（发表 / 保存），纳入编辑器边框内 */
   footer?: ReactNode;
+  /** 正文字符数上限；设置后计数器显示「已输入 / 上限」并限制输入 */
+  maxChars?: number;
   /** 提交失败等原因，显示在编辑器内 */
   error?: string;
   onUploadingChange?: (uploading: boolean) => void;
@@ -143,6 +145,7 @@ export default function MarkdownEditor({
   hint,
   shortcutName,
   footer,
+  maxChars,
   error,
   onUploadingChange,
 }: MarkdownEditorProps) {
@@ -1247,6 +1250,7 @@ export default function MarkdownEditor({
             value={value}
             disabled={disabled}
             rows={isComment ? 3 : rows}
+            maxLength={maxChars}
             placeholder={placeholder}
             aria-label={ariaLabel || placeholder || "正文"}
             className="j13-md-textarea"
@@ -1278,7 +1282,9 @@ export default function MarkdownEditor({
               : "支持粘贴/拖拽图片 · Markdown · Ctrl/⌘ + Enter 提交")}
         </span>
         <span className="j13-md-foot-actions">
-          <span className="j13-md-count tabular-nums">{value.length} 字</span>
+          <span className="j13-md-count tabular-nums">
+            {maxChars != null ? `${value.length} / ${maxChars}` : `${value.length} 字`}
+          </span>
           {footer}
         </span>
       </div>

frontend/components/Modal.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import { useEffect, useRef, type PointerEvent, type ReactNode } from "react";
+import { createPortal } from "react-dom";
 import { X } from "lucide-react";
 
 export type ModalProps = {
@@ -102,7 +103,7 @@ export default function Modal({
     overlayPressedRef.current = false;
   };
 
-  return (
+  return createPortal(
     <div
       className={`fixed inset-0 ${zIndexClass} flex items-center justify-center p-4`}
       style={{ background: "rgba(0,0,0,0.55)" }}
@@ -150,7 +151,8 @@ export default function Modal({
           <div className="flex items-center justify-end gap-2 mt-5">{footer}</div>
         ) : null}
       </div>
-    </div>
+    </div>,
+    document.body
   );
 }
 

frontend/components/NotificationBell.tsx

@@ -3,7 +3,7 @@
 import { useState, useEffect, useRef } from "react";
 import { useRouter } from "next/navigation";
 import Link from "next/link";
-import { Bell, CheckCheck, Heart, MessageCircle, CheckCircle2, XCircle, AtSign, ClipboardList, Award } from "lucide-react";
+import { Bell, CheckCheck, Heart, MessageCircle, CheckCircle2, XCircle, AtSign, ClipboardList, Award, AlertTriangle } from "lucide-react";
 import {
   apiFetchNotifications,
   apiUnreadCount,
@@ -137,17 +137,22 @@ export default function NotificationBell({ initialUnread = 0 }: { initialUnread?
     if (n.type === "pending_review") return "有新内容待审核";
     if (n.type === "deleted") return "删除了你的帖子";
     if (n.type === "badge") return "向你颁布了徽章";
+    if (n.type === "necro_reply") return "旧帖回复提醒";
     return "点赞了你的帖子";
   };
 
   // 审核结果类通知：无互动对象语义，使用专用图标与语义色
   const isApproval = (n: NotificationItem) =>
     n.type === "approved" || n.type === "rejected" || n.type === "deleted";
+  // 系统提醒（ActorID=0）：同样不渲染操作者链接
+  const isSystemNotice = (n: NotificationItem) => n.type === "necro_reply";
   const iconStyle = (n: NotificationItem): { color: string; bg: string; node: React.ReactNode } => {
     if (n.type === "approved")
       return { color: "var(--ok)", bg: "var(--ok-soft)", node: <CheckCircle2 size={15} /> };
     if (n.type === "rejected" || n.type === "deleted")
       return { color: "var(--danger)", bg: "var(--danger-soft)", node: <XCircle size={15} /> };
+    if (n.type === "necro_reply")
+      return { color: "var(--danger)", bg: "var(--danger-soft)", node: <AlertTriangle size={15} /> };
     if (n.type === "like")
       return { color: "var(--clay)", bg: "var(--clay-soft)", node: <Heart size={15} /> };
     if (n.type === "mention")
@@ -223,7 +228,7 @@ export default function NotificationBell({ initialUnread = 0 }: { initialUnread?
             ) : (
               notifications.map((n) => {
                 const ic = iconStyle(n);
-                const approval = isApproval(n);
+                const approval = isApproval(n) || isSystemNotice(n);
                 return (
                 <button
                   key={n.id}

frontend/components/PostActions.tsx

@@ -3,9 +3,9 @@
 import { useState, useEffect, useRef } from "react";
 import { useRouter } from "next/navigation";
 import Link from "next/link";
-import { Pencil, Trash2, Pin, Star, SlidersHorizontal, ChevronDown, Check, BadgeCheck } from "lucide-react";
-import { apiMe, apiDeletePost, apiTogglePin, apiToggleRecommend, apiAdminApprovePost, type User } from "@/lib/api";
-import { canStaffSoftDelete, canModerateBoard, isAdminOrAbove } from "@/lib/roles";
+import { Pencil, Trash2, Pin, Star, SlidersHorizontal, ChevronDown, Check, BadgeCheck, Lock, LockOpen } from "lucide-react";
+import { apiMe, apiDeletePost, apiTogglePin, apiToggleRecommend, apiTogglePostLock, apiAdminApprovePost, type User } from "@/lib/api";
+import { canStaffSoftDelete, canModerateBoard, isAdminOrAbove, isStaff } from "@/lib/roles";
 import { toast } from "@/lib/toast";
 import ConfirmDialog from "@/components/ConfirmDialog";
 import StaffDeletePostModal from "@/components/StaffDeletePostModal";
@@ -19,6 +19,12 @@ interface PostActionsProps {
   recommended: boolean;
   /** 帖子审核状态：pending 时对可审者显示「通过评审」 */
   status: string;
+  /** 帖子创建时间：自动编辑锁计时基准（staff 豁免） */
+  createdAt: string;
+  /** 帖子是否被管理员手动锁定（staff 豁免） */
+  locked: boolean;
+  /** 帖子可编辑时长（小时）；0=不锁定；staff 豁免 */
+  postEditLockHours: number;
   /** 供删除确认展示 */
   title?: string;
 }
@@ -31,6 +37,9 @@ export default function PostActions({
   pinned,
   recommended,
   status,
+  createdAt,
+  locked,
+  postEditLockHours,
   title,
 }: PostActionsProps) {
   const router = useRouter();
@@ -39,6 +48,7 @@ export default function PostActions({
   const [deleting, setDeleting] = useState(false);
   const [isPinned, setIsPinned] = useState(pinned > 0);
   const [isRecommended, setIsRecommended] = useState(recommended);
+  const [isLocked, setIsLocked] = useState(locked);
   const [acting, setActing] = useState(false);
   const [confirmDelete, setConfirmDelete] = useState(false);
   const [staffDeleteOpen, setStaffDeleteOpen] = useState(false);
@@ -70,6 +80,13 @@ export default function PostActions({
     !!user &&
     (user.id === authorId || canStaffSoftDelete(user, boardId, authorRole));
   const isAdmin = !!user && isAdminOrAbove(user.role);
+  const staffUser = !!user && isStaff(user.role);
+  // 编辑入口：手动锁帖或超过可编辑时限时对普通用户隐藏，staff 豁免
+  const editTimeLocked =
+    !staffUser &&
+    postEditLockHours > 0 &&
+    Date.now() - new Date(createdAt).getTime() > postEditLockHours * 3_600_000;
+  const showEdit = canManage && !(isLocked && !staffUser) && !editTimeLocked;
   const canApprove =
     !!user && status === "pending" && canModerateBoard(user, boardId);
   // staff 删他人帖：走类型+理由；作者自删：简单确认
@@ -139,6 +156,21 @@ export default function PostActions({
     }
   };
 
+  const handleLock = async () => {
+    setActing(true);
+    setOpen(false);
+    try {
+      const res = await apiTogglePostLock(postId);
+      setIsLocked(res.locked);
+      toast(res.locked ? "已锁定，普通用户不可编辑与回复" : "已解除锁定", "ok");
+      router.refresh();
+    } catch {
+      toast("操作失败，请稍后重试");
+    } finally {
+      setActing(false);
+    }
+  };
+
   if (!canManage) return null;
 
   const itemCls =
@@ -212,18 +244,35 @@ export default function PostActions({
                 <span className="flex-1 text-left">{isRecommended ? "取消推荐" : "推荐"}</span>
                 {isRecommended && <Check size={14} className="shrink-0" />}
               </button>
+              <button
+                type="button"
+                role="menuitem"
+                onClick={handleLock}
+                className={itemCls}
+                style={isLocked ? { color: "var(--danger)" } : { color: "var(--ink)" }}
+              >
+                {isLocked ? (
+                  <LockOpen size={14} className="shrink-0" />
+                ) : (
+                  <Lock size={14} className="shrink-0" />
+                )}
+                <span className="flex-1 text-left">{isLocked ? "解除锁定" : "锁定"}</span>
+                {isLocked && <Check size={14} className="shrink-0" />}
+              </button>
               <div style={{ height: 1, background: "var(--line)" }} />
             </>
           )}
-          <Link
-            href={`/post/${postId}/edit`}
-            role="menuitem"
-            className={`${itemCls} items-center`}
-            style={{ color: "var(--ink)" }}
-          >
-            <Pencil size={14} className="shrink-0" />
-            <span className="flex-1 text-left">编辑帖子</span>
-          </Link>
+          {showEdit && (
+            <Link
+              href={`/post/${postId}/edit`}
+              role="menuitem"
+              className={`${itemCls} items-center`}
+              style={{ color: "var(--ink)" }}
+            >
+              <Pencil size={14} className="shrink-0" />
+              <span className="flex-1 text-left">编辑帖子</span>
+            </Link>
+          )}
           <button
             type="button"
             role="menuitem"

frontend/components/PostComposer.tsx

@@ -37,6 +37,8 @@ import Modal from "@/components/Modal";
 import { realtime, RT_SETTINGS_CHANGED, type RtSettingsData } from "@/lib/realtime";
 
 const TITLE_MAX = 256;
+/** 帖子正文字符上限（与后端 handler/post.go 校验一致） */
+const CONTENT_MAX = 20000;
 const DRAFT_KEY = "j13-compose-draft";
 const DRAFT_DEBOUNCE_MS = 600;
 /** 与 globals.css 工作台分栏断点一致 */
@@ -1640,7 +1642,8 @@ export default function PostComposer(props: PostComposerProps) {
             <MarkdownEditor
               id="compose-content"
               value={content}
-              onChange={setContent}
+              onChange={(v) => setContent(v.slice(0, CONTENT_MAX))}
+              maxChars={CONTENT_MAX}
               allowHide
               disabled={loading}
               rows={18}

frontend/components/PostEditedMark.tsx

@@ -0,0 +1,37 @@
+"use client";
+
+import { useState } from "react";
+import EditHistoryModal from "@/components/EditHistoryModal";
+import { apiPostHistory } from "@/lib/api";
+
+/** 帖子详情「更新于」旁的编辑历史入口（登录用户可见） */
+export default function PostEditedMark({
+  postId,
+  currentTitle,
+  currentContent,
+}: {
+  postId: number;
+  currentTitle: string;
+  currentContent: string;
+}) {
+  const [open, setOpen] = useState(false);
+  return (
+    <>
+      <button
+        type="button"
+        className="cmt-edited"
+        onClick={() => setOpen(true)}
+      >
+        编辑历史
+      </button>
+      <EditHistoryModal
+        open={open}
+        title="帖子编辑历史"
+        currentTitle={currentTitle}
+        currentContent={currentContent}
+        fetchPage={(p, s) => apiPostHistory(postId, p, s)}
+        onClose={() => setOpen(false)}
+      />
+    </>
+  );
+}

frontend/lib/api.ts

@@ -381,11 +381,19 @@ export interface Post {
   type_status?: string;
   pinned: number;
   recommended: boolean;
+  /** 管理员手动锁定：普通用户不可编辑/回复（staff 豁免） */
+  locked: boolean;
+  /** 最后一条已发布评论时间；null=无回复（旧帖判定回落 created_at） */
+  last_reply_at?: string | null;
+  /** 旧帖回复确认提示（详情接口按查看者计算；存在时提交回复前需用户确认） */
+  necro_reply?: { after_hours: number; penalty: number } | null;
   status: string;
   like_count: number;
   view_count: number;
   comment_count: number;
   liked: boolean;
+  /** 详情接口返回：是否存在编辑历史快照（列表接口无此字段） */
+  edited?: boolean;
   created_at: string;
   updated_at: string;
   board: Board;
@@ -608,7 +616,7 @@ export interface NotificationItem {
   id: number;
   user_id: number;
   actor_id: number;
-  type: "comment" | "reply" | "like" | "approved" | "rejected" | "mention" | "pending_review" | "deleted" | "badge";
+  type: "comment" | "reply" | "like" | "approved" | "rejected" | "mention" | "pending_review" | "deleted" | "badge" | "necro_reply";
   post_id: number;
   comment_id: number;
   room_id?: number;
@@ -918,6 +926,14 @@ export interface PublicSettings {
   points_reply_daily_cap: number;
   /** 帖子被推荐奖励（每帖仅一次）；0=关闭；缺省 0 */
   points_recommend_reward: number;
+  /** 帖子可编辑时长（小时）；0=不锁定；缺省 0；上限 8760 */
+  post_edit_lock_hours: number;
+  /** 评论可编辑时长（小时）；0=不锁定；缺省 0；上限 8760 */
+  comment_edit_lock_hours: number;
+  /** 旧帖回复判定时长（小时）；0=关闭；缺省 0 */
+  necro_reply_after_hours: number;
+  /** 旧帖回复扣除积分；0=仅提醒不扣分；缺省 0；上限 100 */
+  necro_reply_penalty: number;
   /** 用户等级体系（数量/每级阈值/每级色板 key）；等级数值由后端计算 */
   levels: LevelDef[];
   /** 等级特效动画总开关（流光动画）；缺省开 */
@@ -980,6 +996,10 @@ const DEFAULT_PUBLIC_SETTINGS: PublicSettings = {
   points_reply_reward: 0,
   points_reply_daily_cap: 0,
   points_recommend_reward: 0,
+  post_edit_lock_hours: 0,
+  comment_edit_lock_hours: 0,
+  necro_reply_after_hours: 0,
+  necro_reply_penalty: 0,
   levels: [...DEFAULT_LEVEL_DEFS],
   levels_fx: true,
 };
@@ -1068,11 +1088,40 @@ function normalizePublicSettings(data: Partial<PublicSettings> | null | undefine
     bg_admin_url: typeof data?.bg_admin_url === "string" ? data.bg_admin_url : "",
     bg_admin_mode: typeof data?.bg_admin_mode === "string" ? data.bg_admin_mode : "cover",
     ...normalizePointsSettings(data),
+    ...normalizeLockSettings(data),
     levels: normalizeLevels(data?.levels),
     levels_fx: data?.levels_fx !== false,
   };
 }
 
+/** 内容锁定 4 键：小时 0–8760 / 积分 0–100 有效整数，越界/异常回落默认值 */
+function normalizeLockSettings(
+  data: Partial<PublicSettings> | null | undefined,
+): Pick<
+  PublicSettings,
+  | "post_edit_lock_hours"
+  | "comment_edit_lock_hours"
+  | "necro_reply_after_hours"
+  | "necro_reply_penalty"
+> {
+  const hours = (key: keyof PublicSettings): number | undefined => {
+    const v = data?.[key];
+    return typeof v === "number" && v >= 0 && v <= 8760 ? Math.round(v) : undefined;
+  };
+  const points = (key: keyof PublicSettings): number | undefined => {
+    const v = data?.[key];
+    return typeof v === "number" && v >= 0 && v <= 100 ? Math.round(v) : undefined;
+  };
+  return {
+    post_edit_lock_hours: hours("post_edit_lock_hours") ?? DEFAULT_PUBLIC_SETTINGS.post_edit_lock_hours,
+    comment_edit_lock_hours:
+      hours("comment_edit_lock_hours") ?? DEFAULT_PUBLIC_SETTINGS.comment_edit_lock_hours,
+    necro_reply_after_hours:
+      hours("necro_reply_after_hours") ?? DEFAULT_PUBLIC_SETTINGS.necro_reply_after_hours,
+    necro_reply_penalty: points("necro_reply_penalty") ?? DEFAULT_PUBLIC_SETTINGS.necro_reply_penalty,
+  };
+}
+
 /** 积分规则 8 键：0–100 有效整数，越界/异常回落默认值 */
 function normalizePointsSettings(
   data: Partial<PublicSettings> | null | undefined,
@@ -1977,6 +2026,15 @@ export async function apiToggleRecommend(postId: string): Promise<{ recommended:
   return res.json();
 }
 
+/** 切换帖子手动锁定（管理员及以上）；锁定后普通用户不可编辑/回复 */
+export async function apiTogglePostLock(postId: string): Promise<{ locked: boolean }> {
+  const res = await fetchWithRefresh(`/api/posts/${postId}/lock`, {
+    method: "PUT",
+    headers: clientHeaders(),
+  });
+  return res.json();
+}
+
 export async function apiChangePassword(oldPassword: string, newPassword: string) {
   const res = await fetchWithRefresh("/api/change-password", {
     method: "POST",
@@ -3092,6 +3150,10 @@ export type UpdateSiteSettingsBody = {
   points_reply_reward?: number;
   points_reply_daily_cap?: number;
   points_recommend_reward?: number;
+  post_edit_lock_hours?: number;
+  comment_edit_lock_hours?: number;
+  necro_reply_after_hours?: number;
+  necro_reply_penalty?: number;
   /** 用户等级体系（数量/每级阈值/每级色板 key）；整体替换保存 */
   levels?: LevelDef[];
   levels_fx?: boolean;
@@ -3264,6 +3326,8 @@ export interface AdminContentComment {
   board_id: number;
   content: string;
   status: string;
+  /** 相对创建已编辑（服务端判定）；无编辑时隐藏历史入口 */
+  edited: boolean;
   deleted: boolean;
   deleted_at?: string;
   created_at: string;
@@ -3352,15 +3416,44 @@ export interface CommentEditHistoryItem {
   created_at: string;
 }
 
-/** 管理：评论编辑历史（分页；默认每页 10 条） */
-export async function apiAdminCommentHistory(
+/** 评论编辑历史（登录可见；分页；默认每页 10 条） */
+export async function apiCommentHistory(
   commentId: number,
   page = 1,
   size = 10
 ): Promise<{ items: CommentEditHistoryItem[]; total: number; page: number; size: number }> {
   const params = new URLSearchParams({ page: String(page), size: String(size) });
   const res = await fetchWithRefresh(
-    `/api/admin/content/comments/${commentId}/history?${params}`,
+    `/api/comments/${commentId}/history?${params}`,
+    { headers: clientHeaders() }
+  );
+  const data = await res.json().catch(() => ({}));
+  if (!res.ok) throw new Error(data.error || "获取编辑历史失败");
+  return data;
+}
+
+export interface PostEditHistoryItem {
+  id: number;
+  editor: {
+    id: number;
+    username: string;
+    nickname: string;
+    avatar: string;
+  };
+  old_title: string;
+  old_content: string;
+  created_at: string;
+}
+
+/** 帖子编辑历史（登录可见；分页；默认每页 10 条） */
+export async function apiPostHistory(
+  postId: number,
+  page = 1,
+  size = 10
+): Promise<{ items: PostEditHistoryItem[]; total: number; page: number; size: number }> {
+  const params = new URLSearchParams({ page: String(page), size: String(size) });
+  const res = await fetchWithRefresh(
+    `/api/posts/${postId}/history?${params}`,
     { headers: clientHeaders() }
   );
   const data = await res.json().catch(() => ({}));

frontend/lib/smartDiff.test.ts

@@ -0,0 +1,214 @@
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+import { smartDiff, toFoldedRows } from "./smartDiff.ts";
+
+/** 把结果压成便于断言的短格式：每行 "op:text" */
+function flat(text: string, other: string): string[] {
+  const r = smartDiff(text, other);
+  return r.blocks.flatMap((b) => b.lines.map((l) => `${l.op}:${l.text}`));
+}
+
+describe("smartDiff", () => {
+  it("场景1：整段中文说明 → 整段 R 代码，判定 block-replace 而非碎片对齐", () => {
+    // 两段各留一个空行作为「诱饵公共行」——朴素 LCS 会围绕它做对齐
+    const oldText = [
+      "本函数用于处理用户上传的数据。",
+      "",
+      "首先校验输入的合法性，",
+      "然后将数据逐行写入临时表，",
+      "最后清理缓存并返回结果。",
+    ].join("\n");
+    const newText = [
+      "process_data <- function(df) {",
+      "",
+      "  stopifnot(!is.null(df))",
+      "  out <- transform(df, total = sum(x))",
+      '  write.csv(out, "out.csv")',
+      "  invisible(out)",
+      "}",
+    ].join("\n");
+
+    const r = smartDiff(oldText, newText);
+    assert.equal(r.blocks.length, 1);
+    assert.equal(r.blocks[0].type, "block-replace");
+    // 大删除块在前、大新增块在后，不出现 -/+ 交替碎片
+    const ops = r.blocks[0].lines.map((l) => l.op);
+    assert.ok(ops.slice(0, 5).every((o) => o === "del"));
+    assert.ok(ops.slice(5).every((o) => o === "ins"));
+    assert.equal(r.stats.dels, 5);
+    assert.equal(r.stats.adds, 7);
+    // 整段替换不做行内细分
+    assert.ok(r.blocks[0].lines.every((l) => l.segments === undefined));
+  });
+
+  it("场景2：单行内改一个词，输出词级 segments 而非整行标红标绿", () => {
+    const oldText = "const total = countItems(list);";
+    const newText = "const total = countUsers(list);";
+    const r = smartDiff(oldText, newText);
+    assert.equal(r.blocks.length, 1);
+    assert.equal(r.blocks[0].type, "replace");
+    const del = r.blocks[0].lines[0];
+    const ins = r.blocks[0].lines[1];
+    assert.ok(del.segments && del.segments.length > 0, "del 行应有 segments");
+    assert.ok(ins.segments && ins.segments.length > 0, "ins 行应有 segments");
+    // 删除行上被标记的正是 countItems，新增行上是 countUsers
+    const delMarked = del.segments!.map((s) => del.text.slice(s.start, s.end)).join("");
+    const insMarked = ins.segments!.map((s) => ins.text.slice(s.start, s.end)).join("");
+    assert.equal(delMarked, "countItems");
+    assert.equal(insMarked, "countUsers");
+    // 片段不应包含未变化的部分
+    for (const s of del.segments!) {
+      assert.ok(!del.text.slice(s.start, s.end).includes("const"));
+    }
+  });
+
+  it("场景3：仅行尾空白变化，不产生假改动", () => {
+    const oldText = "第一行   \n第二行\t";
+    const newText = "第一行\n第二行";
+    const r = smartDiff(oldText, newText);
+    assert.equal(r.blocks.length, 1);
+    assert.equal(r.blocks[0].type, "equal");
+    assert.deepEqual(r.stats, { adds: 0, dels: 0 });
+    // 展示保留原文（含行尾空白），但比较视为相同
+    assert.equal(r.blocks[0].lines[0].text, "第一行   ");
+  });
+
+  it("场景4：大量重复空行/花括号的代码，对齐不错位、变更块不碎", () => {
+    const oldText = [
+      "function a() {",
+      "",
+      "  if (x) {",
+      "",
+      "    return 1;",
+      "",
+      "  }",
+      "",
+      "}",
+    ].join("\n");
+    const newText = [
+      "function a() {",
+      "",
+      "  if (y) {",
+      "",
+      "    return 2;",
+      "",
+      "  }",
+      "",
+      "}",
+    ].join("\n");
+
+    const r = smartDiff(oldText, newText);
+    // 期望：equal → replace(if 行) → equal → replace(return 行) → equal
+    assert.deepEqual(
+      r.blocks.map((b) => b.type),
+      ["equal", "replace", "equal", "replace", "equal"]
+    );
+    // 两个 replace 块均有行内细分，且只标记真正变化的字符
+    const [b1, b2] = [r.blocks[1], r.blocks[3]];
+    assert.equal(b1.lines[0].text, "  if (x) {");
+    assert.equal(
+      b1.lines[0].segments!.map((s) => b1.lines[0].text.slice(s.start, s.end)).join(""),
+      "x"
+    );
+    assert.equal(
+      b1.lines[1].segments!.map((s) => b1.lines[1].text.slice(s.start, s.end)).join(""),
+      "y"
+    );
+    assert.equal(
+      b2.lines[0].segments!.map((s) => b2.lines[0].text.slice(s.start, s.end)).join(""),
+      "1"
+    );
+    // 空行不进入任何变更块
+    assert.ok(r.blocks.every((b) => b.type === "equal" || !b.lines.some((l) => l.text === "")));
+  });
+
+  it("场景5：完全相同的文本，只有一个 equal 块", () => {
+    const text = "第一行\n第二行\n第三行";
+    const r = smartDiff(text, text);
+    assert.equal(r.blocks.length, 1);
+    assert.equal(r.blocks[0].type, "equal");
+    assert.equal(r.blocks[0].lines.length, 3);
+    assert.deepEqual(r.stats, { adds: 0, dels: 0 });
+  });
+
+  it("CRLF / CR 行尾符差异不影响比较", () => {
+    const r = smartDiff("a\r\nb\rc", "a\nb\nc");
+    assert.equal(r.blocks.length, 1);
+    assert.equal(r.blocks[0].type, "equal");
+    assert.deepEqual(r.stats, { adds: 0, dels: 0 });
+  });
+
+  it("单侧为空：整体删除 / 整体新增", () => {
+    const ins = smartDiff("", "新的一行\n再来一行");
+    assert.deepEqual(ins.blocks.map((b) => b.type), ["insert"]);
+    assert.equal(ins.stats.adds, 2);
+
+    const del = smartDiff("旧行一\n旧行二", "");
+    assert.deepEqual(del.blocks.map((b) => b.type), ["delete"]);
+    assert.equal(del.stats.dels, 2);
+
+    assert.deepEqual(smartDiff("", "").blocks, []);
+  });
+
+  it("后处理不变式：相邻同向块必合并，replace 块内 del 全部在 ins 之前", () => {
+    const oldText = Array.from({ length: 30 }, (_, i) => `common ${i}`).join("\n");
+    const newText = oldText
+      .replace("common 5", "changed 5")
+      .replace("common 6", "changed 6")
+      .replace("common 20", "changed 20");
+    const r = smartDiff(oldText, newText);
+    // 相邻块不允许同为变更块（equal 必然隔开两个变更区域）
+    for (let i = 1; i < r.blocks.length; i++) {
+      const prev = r.blocks[i - 1];
+      const cur = r.blocks[i];
+      assert.ok(
+        !(prev.type !== "equal" && cur.type !== "equal"),
+        "相邻变更块未被合并"
+      );
+    }
+    for (const b of r.blocks) {
+      if (b.type !== "replace") continue;
+      const firstIns = b.lines.findIndex((l) => l.op === "ins");
+      const lastDel = b.lines.map((l) => l.op).lastIndexOf("del");
+      assert.ok(lastDel < firstIns, "replace 块内应先删后增");
+    }
+  });
+
+  it("上下文折叠：长 equal 块折叠为上下文 + 省略标记，头/尾单侧保留", () => {
+    const lines = Array.from({ length: 40 }, (_, i) => `L${i}`);
+    const oldText = lines.join("\n");
+    const newText = [...lines.slice(0, 20), "changed", ...lines.slice(21)].join("\n");
+    const rows = toFoldedRows(smartDiff(oldText, newText).blocks);
+    // 头部 equal 块（L0..L19，isHead）只保留尾部 3 行上下文 L17/L18/L19 + 折叠 17 行；
+    // 尾部 equal 块（L21..L39，isTail）只保留头部 3 行上下文 L21/L22/L23 + 折叠 16 行
+    const folds = rows.filter((r) => r.kind === "fold") as Array<{ kind: "fold"; count: number }>;
+    assert.deepEqual(
+      folds.map((f) => f.count),
+      [17, 16]
+    );
+    // 头部 equal 块（L0..L19，isHead）：省略前 17 行 → 保留尾部上下文 L17/L18/L19；
+    // 尾部 equal 块（L21..L39，isTail）：保留头部上下文 L21/L22/L23 → 省略后 16 行
+    assert.deepEqual(rows.slice(0, 4).map((r) => (r.kind === "fold" ? "fold" : r.text)), [
+      "fold",
+      "L17",
+      "L18",
+      "L19",
+    ]);
+  });
+
+  it("10 万行大文件在 2 秒内完成", () => {
+    const n = 100_000;
+    const oldLines = Array.from({ length: n }, (_, i) => `line-${i}`);
+    const newLines = [...oldLines];
+    const changes = 20;
+    for (let k = 0; k < changes; k++) {
+      newLines[k * 4_000 + 7] = `line-${k * 4_000 + 7}-changed`;
+    }
+    const start = performance.now();
+    const r = smartDiff(oldLines.join("\n"), newLines.join("\n"));
+    const elapsed = performance.now() - start;
+    assert.equal(r.stats.dels, changes);
+    assert.equal(r.stats.adds, changes);
+    assert.ok(elapsed < 2_000, `应在 2 秒内完成，实际 ${elapsed.toFixed(0)}ms`);
+  });
+});

frontend/lib/smartDiff.ts

@@ -0,0 +1,527 @@
+/**
+ * smartDiff —— 面向可读性的结构化行级 diff（自研，无第三方依赖）。
+ *
+ * 四层处理：
+ * 1. 预处理：CRLF/CR → LF（仅用于比较与展示），行尾空白在比较时忽略（展示保留原文）。
+ * 2. 算法选择：行级相似度（difflib ratio 思路：2M/(a+b)，M 为多重集交集）低于阈值时
+ *    判定「整段替换」，输出一个 block-replace，跳过逐行对齐——避免把毫无对应关系的
+ *    两段文本切成几十对 -/+ 碎片；否则用 Patience diff（锚定双方唯一行，LIS 选链），
+ *    无锚点/超大规模/超深递归的子区间回退为 LCS 或整块替换。
+ * 3. 后处理：相邻同向变更合并为一个块（del 在前 ins 在后），消除 LCS 的交叉配对；
+ *    上下文折叠（默认 3 行，头/尾块只保留单侧上下文）。
+ * 4. 行内细分：replace 块内按下标配对的行对，先分词（CJK 单字、西文单词、空白、符号），
+ *    词级 LCS 相似度 > 阈值时输出变更片段的字符偏移（segments），否则整行视为变更。
+ *
+ * 输出为结构化块数组，供 diff 视图组件渲染；segments 直接挂在对应行上
+ * （start/end 为该行文本的 UTF-16 偏移），UI 只高亮变更部分。
+ */
+
+export type LineOp = "equal" | "del" | "ins";
+export type BlockType = "equal" | "insert" | "delete" | "replace" | "block-replace";
+
+/** 行内变更片段：start/end 为行文本的 UTF-16 偏移，type 为该行视角下的变更方向 */
+export interface InlineSegment {
+  start: number;
+  end: number;
+  type: "del" | "ins";
+}
+
+export interface DiffLine {
+  op: LineOp;
+  /** 原始行文本（保留行尾空白，供展示） */
+  text: string;
+  /** 仅 replace 块中被判定为「修改」的行对附带；缺省表示整行变更 */
+  segments?: InlineSegment[];
+}
+
+export interface DiffBlock {
+  type: BlockType;
+  lines: DiffLine[];
+}
+
+export interface DiffStats {
+  adds: number;
+  dels: number;
+}
+
+export interface DiffResult {
+  blocks: DiffBlock[];
+  stats: DiffStats;
+}
+
+export interface SmartDiffOptions {
+  /** 行级相似度低于该值判定整段替换（默认 0.2；仅任一侧 ≥2 行时生效） */
+  replaceThreshold?: number;
+  /** 行对词级相似度高于该值才做行内细分（默认 0.6） */
+  inlineThreshold?: number;
+}
+
+// 行级 LCS 回退的规模上限（超出则该区间整块替换，避免 O(n·m) 爆炸）
+const MAX_REGION_CELLS = 400_000;
+// 行内词级 LCS 的 token 数上限
+const MAX_INLINE_CELLS = 20_000;
+// 行对合计字符数超过则跳过行内细分
+const MAX_INLINE_CHARS = 4_000;
+// Patience 递归深度上限（超过直接整块替换，防御构造性深递归）
+const MAX_PATIENCE_DEPTH = 32;
+
+/* ---------------- 第一层：预处理 ---------------- */
+
+interface SplitText {
+  raw: string[];
+  /** 归一化后的行（比较用）：行尾空白已去除 */
+  cmp: string[];
+}
+
+function splitLines(text: string): SplitText {
+  const norm = text.replace(/\r\n?/g, "\n");
+  const raw = norm === "" ? [] : norm.split("\n");
+  return { raw, cmp: raw.map((l) => l.replace(/\s+$/, "")) };
+}
+
+/* ---------------- 第二层：相似度与算法选择 ---------------- */
+
+/** 行级相似度：difflib ratio 思路，2M/(a+b)，M 为行多重集交集大小 */
+function lineSimilarity(a: string[], b: string[]): number {
+  if (a.length === 0 && b.length === 0) return 1;
+  const freq = new Map<string, number>();
+  for (const l of a) freq.set(l, (freq.get(l) ?? 0) + 1);
+  let m = 0;
+  for (const l of b) {
+    const c = freq.get(l) ?? 0;
+    if (c > 0) {
+      m += 1;
+      freq.set(l, c - 1);
+    }
+  }
+  return (2 * m) / (a.length + b.length);
+}
+
+type RawOp = { op: LineOp; ai: number; bi: number };
+
+/**
+ * Patience diff：在区间内找到「双方都恰好出现一次」的公共行作锚点，
+ * 对锚点按 i 升序求 j 的最长递增子序列（patience sorting，O(k log k)）作骨架，
+ * 骨架之间的间隙递归；无锚点/超深的区间回退 fallbackRegion。
+ */
+function patienceDiff(
+  cmpA: string[],
+  cmpB: string[],
+  loA: number,
+  hiA: number,
+  loB: number,
+  hiB: number,
+  out: RawOp[],
+  depth: number
+): void {
+  if (loA >= hiA && loB >= hiB) return;
+
+  const countA = new Map<string, number>();
+  for (let i = loA; i < hiA; i++) countA.set(cmpA[i], (countA.get(cmpA[i]) ?? 0) + 1);
+  const countB = new Map<string, number>();
+  for (let j = loB; j < hiB; j++) countB.set(cmpB[j], (countB.get(cmpB[j]) ?? 0) + 1);
+
+  const posA = new Map<string, number>();
+  for (let i = loA; i < hiA; i++) {
+    if (countA.get(cmpA[i]) === 1) posA.set(cmpA[i], i);
+  }
+  const anchors: Array<{ i: number; j: number }> = [];
+  for (let j = loB; j < hiB; j++) {
+    if (countB.get(cmpB[j]) === 1) {
+      const i = posA.get(cmpB[j]);
+      if (i !== undefined) anchors.push({ i, j });
+    }
+  }
+  if (anchors.length === 0 || depth >= MAX_PATIENCE_DEPTH) {
+    fallbackRegion(cmpA, cmpB, loA, hiA, loB, hiB, out);
+    return;
+  }
+
+  anchors.sort((x, y) => x.i - y.i);
+  const tails: number[] = [];
+  const prev = new Array<number>(anchors.length).fill(-1);
+  for (let k = 0; k < anchors.length; k++) {
+    const j = anchors[k].j;
+    let lo = 0;
+    let hi = tails.length;
+    while (lo < hi) {
+      const mid = (lo + hi) >> 1;
+      if (anchors[tails[mid]].j < j) lo = mid + 1;
+      else hi = mid;
+    }
+    if (lo > 0) prev[k] = tails[lo - 1];
+    if (lo === tails.length) tails.push(k);
+    else tails[lo] = k;
+  }
+  const chain: number[] = [];
+  for (let k = tails[tails.length - 1]; k !== -1; k = prev[k]) chain.push(k);
+  chain.reverse();
+
+  let ai = loA;
+  let bi = loB;
+  for (const k of chain) {
+    const { i, j } = anchors[k];
+    patienceDiff(cmpA, cmpB, ai, i, bi, j, out, depth + 1);
+    out.push({ op: "equal", ai: i, bi: j });
+    ai = i + 1;
+    bi = j + 1;
+  }
+  patienceDiff(cmpA, cmpB, ai, hiA, bi, hiB, out, depth + 1);
+}
+
+/** 无锚点区间：无公共行或规模超限时整块替换；否则 LCS 细对齐 */
+function fallbackRegion(
+  cmpA: string[],
+  cmpB: string[],
+  loA: number,
+  hiA: number,
+  loB: number,
+  hiB: number,
+  out: RawOp[]
+): void {
+  const n = hiA - loA;
+  const m = hiB - loB;
+  if (n === 0 && m === 0) return;
+  if (n === 0) {
+    for (let j = loB; j < hiB; j++) out.push({ op: "ins", ai: loA, bi: j });
+    return;
+  }
+  if (m === 0) {
+    for (let i = loA; i < hiA; i++) out.push({ op: "del", ai: i, bi: loB });
+    return;
+  }
+  if (n * m > MAX_REGION_CELLS || !hasCommonLine(cmpA, cmpB, loA, hiA, loB, hiB)) {
+    for (let i = loA; i < hiA; i++) out.push({ op: "del", ai: i, bi: loB });
+    for (let j = loB; j < hiB; j++) out.push({ op: "ins", ai: hiA, bi: j });
+    return;
+  }
+  lcsRegion(cmpA, cmpB, loA, hiA, loB, hiB, out);
+}
+
+function hasCommonLine(
+  cmpA: string[],
+  cmpB: string[],
+  loA: number,
+  hiA: number,
+  loB: number,
+  hiB: number
+): boolean {
+  const set = new Set<string>();
+  for (let i = loA; i < hiA; i++) set.add(cmpA[i]);
+  for (let j = loB; j < hiB; j++) {
+    if (set.has(cmpB[j])) return true;
+  }
+  return false;
+}
+
+/** 行级 LCS（规模已由调用方限制），供无锚点但有公共行的区间使用 */
+function lcsRegion(
+  cmpA: string[],
+  cmpB: string[],
+  loA: number,
+  hiA: number,
+  loB: number,
+  hiB: number,
+  out: RawOp[]
+): void {
+  const n = hiA - loA;
+  const m = hiB - loB;
+  const width = m + 1;
+  const dp = new Uint32Array((n + 1) * width);
+  for (let i = n - 1; i >= 0; i--) {
+    const aLine = cmpA[loA + i];
+    for (let j = m - 1; j >= 0; j--) {
+      dp[i * width + j] =
+        aLine === cmpB[loB + j]
+          ? dp[(i + 1) * width + (j + 1)] + 1
+          : Math.max(dp[(i + 1) * width + j], dp[i * width + (j + 1)]);
+    }
+  }
+  let i = 0;
+  let j = 0;
+  while (i < n && j < m) {
+    if (cmpA[loA + i] === cmpB[loB + j]) {
+      out.push({ op: "equal", ai: loA + i, bi: loB + j });
+      i += 1;
+      j += 1;
+    } else if (dp[(i + 1) * width + j] >= dp[i * width + (j + 1)]) {
+      out.push({ op: "del", ai: loA + i, bi: loB + j });
+      i += 1;
+    } else {
+      out.push({ op: "ins", ai: loA + i, bi: loB + j });
+      j += 1;
+    }
+  }
+  while (i < n) {
+    out.push({ op: "del", ai: loA + i, bi: loB + j });
+    i += 1;
+  }
+  while (j < m) {
+    out.push({ op: "ins", ai: loA + i, bi: loB + j });
+    j += 1;
+  }
+}
+
+/* ---------------- 第三层：后处理（块构建 + 上下文折叠） ---------------- */
+
+/**
+ * 把扁平 op 序列整理成块：
+ * - 连续 equal → equal 块（展示用旧文本原文）
+ * - 连续非 equal 合并为一个变更区域：del 按原顺序在前、ins 按新顺序在后，
+ *   两侧都有 → replace（后续做行内细分），单侧 → delete / insert。
+ * 这一步消除了 LCS 可能出现的 -/+ 交叉碎片（del,ins,del,ins → 一个 replace 块）。
+ */
+function buildBlocks(ops: RawOp[], rawA: string[], rawB: string[]): DiffBlock[] {
+  const blocks: DiffBlock[] = [];
+  let k = 0;
+  while (k < ops.length) {
+    if (ops[k].op === "equal") {
+      const lines: DiffLine[] = [];
+      while (k < ops.length && ops[k].op === "equal") {
+        lines.push({ op: "equal", text: rawA[ops[k].ai] });
+        k += 1;
+      }
+      blocks.push({ type: "equal", lines });
+      continue;
+    }
+    const dels: DiffLine[] = [];
+    const inss: DiffLine[] = [];
+    while (k < ops.length && ops[k].op !== "equal") {
+      const o = ops[k];
+      if (o.op === "del") dels.push({ op: "del", text: rawA[o.ai] });
+      else inss.push({ op: "ins", text: rawB[o.bi] });
+      k += 1;
+    }
+    const type: BlockType =
+      dels.length > 0 && inss.length > 0 ? "replace" : dels.length > 0 ? "delete" : "insert";
+    blocks.push({ type, lines: [...dels, ...inss] });
+  }
+  return blocks;
+}
+
+export type FoldedRow =
+  | { kind: "line"; op: LineOp; text: string; segments?: InlineSegment[] }
+  | { kind: "fold"; count: number };
+
+/**
+ * 上下文折叠：超过 context*2+2 行的 equal 块只保留变更两侧各 context 行，
+ * 头/尾 equal 块只保留单侧；返回渲染用的行序列（fold 为折叠标记）。
+ */
+export function toFoldedRows(blocks: DiffBlock[], context = 3): FoldedRow[] {
+  const rows: FoldedRow[] = [];
+  const pushLine = (l: DiffLine) =>
+    rows.push({ kind: "line", op: l.op, text: l.text, segments: l.segments });
+  blocks.forEach((b, bi) => {
+    if (!(b.type === "equal" && b.lines.length > context * 2 + 2)) {
+      b.lines.forEach(pushLine);
+      return;
+    }
+    const isHead = bi === 0;
+    const isTail = bi === blocks.length - 1;
+    if (isHead && isTail) {
+      // 整个 diff 都是相同内容：不折叠
+      b.lines.forEach(pushLine);
+      return;
+    }
+    const head = isHead ? 0 : context;
+    const tail = isTail ? 0 : context;
+    for (let i = 0; i < head; i++) pushLine(b.lines[i]);
+    rows.push({ kind: "fold", count: b.lines.length - head - tail });
+    for (let i = b.lines.length - tail; i < b.lines.length; i++) pushLine(b.lines[i]);
+  });
+  return rows;
+}
+
+/* ---------------- 第四层：行内细分（词级 diff） ---------------- */
+
+// CJK 逐字成 token（中文无词边界），西文按单词，空白连续，其余单字符
+const TOKEN_RE = /[\p{Script=Han}\p{Script=Hiragana}\p{Script=Katakana}\p{Script=Hangul}]|[A-Za-z0-9_]+|\s+|[^\s]/gu;
+
+interface Tokens {
+  tokens: string[];
+  starts: number[];
+  ends: number[];
+}
+
+function tokenize(line: string): Tokens {
+  const tokens: string[] = [];
+  const starts: number[] = [];
+  const ends: number[] = [];
+  for (const m of line.matchAll(TOKEN_RE)) {
+    const start = m.index;
+    if (start === undefined) continue;
+    tokens.push(m[0]);
+    starts.push(start);
+    ends.push(start + m[0].length);
+  }
+  return { tokens, starts, ends };
+}
+
+function lcsTokenLen(a: string[], b: string[]): number {
+  const n = a.length;
+  const m = b.length;
+  const width = m + 1;
+  const dp = new Uint32Array((n + 1) * width);
+  for (let i = n - 1; i >= 0; i--) {
+    for (let j = m - 1; j >= 0; j--) {
+      dp[i * width + j] =
+        a[i] === b[j]
+          ? dp[(i + 1) * width + (j + 1)] + 1
+          : Math.max(dp[(i + 1) * width + j], dp[i * width + (j + 1)]);
+    }
+  }
+  return dp[0];
+}
+
+/** X 视角下的变更片段：词级 LCS 中未被匹配的连续 token 合并为一个字符区间 */
+function changedSegments(
+  t: Tokens,
+  ops: Array<{ op: "equal" | "chg"; idx: number }>,
+  type: "del" | "ins"
+): InlineSegment[] {
+  const segs: InlineSegment[] = [];
+  let cur: InlineSegment | null = null;
+  for (const o of ops) {
+    if (o.op === "equal") {
+      cur = null;
+      continue;
+    }
+    const start = t.starts[o.idx];
+    const end = t.ends[o.idx];
+    if (cur && cur.end === start) {
+      cur.end = end;
+    } else {
+      cur = { start, end, type };
+      segs.push(cur);
+    }
+  }
+  return segs;
+}
+
+/** 词级 LCS 回溯，产出 X/Y 各自的 equal/chg 序列（idx 为各自 token 下标） */
+function tokenOps(x: Tokens, y: Tokens): {
+  xOps: Array<{ op: "equal" | "chg"; idx: number }>;
+  yOps: Array<{ op: "equal" | "chg"; idx: number }>;
+} {
+  const n = x.tokens.length;
+  const m = y.tokens.length;
+  const width = m + 1;
+  const dp = new Uint32Array((n + 1) * width);
+  for (let i = n - 1; i >= 0; i--) {
+    for (let j = m - 1; j >= 0; j--) {
+      dp[i * width + j] =
+        x.tokens[i] === y.tokens[j]
+          ? dp[(i + 1) * width + (j + 1)] + 1
+          : Math.max(dp[(i + 1) * width + j], dp[i * width + (j + 1)]);
+    }
+  }
+  const xOps: Array<{ op: "equal" | "chg"; idx: number }> = [];
+  const yOps: Array<{ op: "equal" | "chg"; idx: number }> = [];
+  let i = 0;
+  let j = 0;
+  while (i < n && j < m) {
+    if (x.tokens[i] === y.tokens[j]) {
+      xOps.push({ op: "equal", idx: i });
+      yOps.push({ op: "equal", idx: j });
+      i += 1;
+      j += 1;
+    } else if (dp[(i + 1) * width + j] >= dp[i * width + (j + 1)]) {
+      xOps.push({ op: "chg", idx: i });
+      i += 1;
+    } else {
+      yOps.push({ op: "chg", idx: j });
+      j += 1;
+    }
+  }
+  while (i < n) {
+    xOps.push({ op: "chg", idx: i });
+    i += 1;
+  }
+  while (j < m) {
+    yOps.push({ op: "chg", idx: j });
+    j += 1;
+  }
+  return { xOps, yOps };
+}
+
+/** 对 replace 块内按下标配对的行对做词级细分；相似度不足则整行变更、不产出 segments */
+function annotateInline(blocks: DiffBlock[], inlineThreshold: number): void {
+  for (const b of blocks) {
+    if (b.type !== "replace") continue;
+    const dels = b.lines.filter((l) => l.op === "del");
+    const inss = b.lines.filter((l) => l.op === "ins");
+    const n = Math.min(dels.length, inss.length);
+    for (let i = 0; i < n; i++) {
+      const delLine = dels[i];
+      const insLine = inss[i];
+      if (delLine.text.length + insLine.text.length > MAX_INLINE_CHARS) continue;
+      const x = tokenize(delLine.text);
+      const y = tokenize(insLine.text);
+      if (x.tokens.length === 0 || y.tokens.length === 0) continue;
+      if (x.tokens.length * y.tokens.length > MAX_INLINE_CELLS) continue;
+      const ratio = (2 * lcsTokenLen(x.tokens, y.tokens)) / (x.tokens.length + y.tokens.length);
+      if (!(ratio > inlineThreshold)) continue;
+      const { xOps, yOps } = tokenOps(x, y);
+      const delSegs = changedSegments(x, xOps, "del");
+      const insSegs = changedSegments(y, yOps, "ins");
+      if (delSegs.length > 0) delLine.segments = delSegs;
+      if (insSegs.length > 0) insLine.segments = insSegs;
+    }
+  }
+}
+
+/* ---------------- 入口 ---------------- */
+
+export function smartDiff(
+  oldText: string,
+  newText: string,
+  options: SmartDiffOptions = {}
+): DiffResult {
+  const replaceThreshold = options.replaceThreshold ?? 0.2;
+  const inlineThreshold = options.inlineThreshold ?? 0.6;
+  const a = splitLines(oldText);
+  const b = splitLines(newText);
+
+  const ops: RawOp[] = [];
+  let wholeReplace = false;
+  if (a.cmp.length === 0 && b.cmp.length === 0) {
+    // 两侧皆空：无块
+  } else if (a.cmp.length === 0 || b.cmp.length === 0) {
+    // 单侧为空：整体删除/新增
+    if (a.cmp.length > 0) {
+      for (let i = 0; i < a.cmp.length; i++) ops.push({ op: "del", ai: i, bi: 0 });
+    } else {
+      for (let j = 0; j < b.cmp.length; j++) ops.push({ op: "ins", ai: 0, bi: j });
+    }
+  } else if (
+    a.cmp.length >= 2 &&
+    b.cmp.length >= 2 &&
+    lineSimilarity(a.cmp, b.cmp) < replaceThreshold
+  ) {
+    // 整段替换：跳过逐行对齐，输出一个大删除块 + 一个大新增块
+    wholeReplace = true;
+    for (let i = 0; i < a.cmp.length; i++) ops.push({ op: "del", ai: i, bi: 0 });
+    for (let j = 0; j < b.cmp.length; j++) ops.push({ op: "ins", ai: 0, bi: j });
+  } else {
+    patienceDiff(a.cmp, b.cmp, 0, a.cmp.length, 0, b.cmp.length, ops, 0);
+  }
+
+  const blocks = buildBlocks(ops, a.raw, b.raw);
+  if (wholeReplace) {
+    // 相似度低于阈值判定为整段替换：唯一变更块标记为 block-replace，
+    // 不做行内细分（两侧内容无对应关系，细对齐只会产出噪音）
+    const blk = blocks.find((x) => x.type === "replace");
+    if (blk) blk.type = "block-replace";
+  }
+  annotateInline(blocks, inlineThreshold);
+
+  let dels = 0;
+  let adds = 0;
+  for (const blk of blocks) {
+    for (const l of blk.lines) {
+      if (l.op === "del") dels += 1;
+      else if (l.op === "ins") adds += 1;
+    }
+  }
+  return { blocks, stats: { adds, dels } };
+}

frontend/package.json

@@ -7,7 +7,7 @@
     "build": "next build",
     "start": "next start -p 3000",
     "lint": "next lint",
-    "test": "node --experimental-strip-types --test lib/siteUrl.test.ts lib/jsonLd.test.ts lib/widgetCode.test.ts"
+    "test": "node --experimental-strip-types --test lib/siteUrl.test.ts lib/jsonLd.test.ts lib/widgetCode.test.ts lib/smartDiff.test.ts"
   },
   "dependencies": {
     "hast-util-to-jsx-runtime": "^2.3.6",