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/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(() => ({}));