feat(ux): 真 404 / HTML 500 页，以及「提问者找回自己的提问」

一、错误页

原来未知路径一律 302 到首页：用户点了个失效链接，地址栏莫名跳到首页却什么
提示都没有，分不清是链接坏了还是自己点错了；对搜索引擎是软 404，失效链接会
被当成有效页面一直占抓取预算。500 则是 flamego.Recovery() 的纯文本
"Internal Server Error"，白底黑字两行英文，没有返回入口，也没法报编号。

现在是 internal/route/errorpage.go 里的 writeErrorPage：
- 404 保留状态码 + 一页能看懂的说明 + 返回首页按钮 + noindex
- panic 由自写的 recoveryMiddleware 兜住，渲染同样的 HTML 500 页，
  并带上 trace id（用户反馈时报这个号就能定位日志），日志里也带完整栈
- 响应已写出时不再写头（否则 net/http 会忽略状态码并打 superfluous 警告）

为什么不套模板：f.NotFound 不经过组级中间件 —— template.Templater 与
Contexter（连同 session、CSRF）都挂在 f.Group 上，在 NotFound 里注入
template.Data 会直接 panic（实测："value not found for type template.Data"）。
而 recovery 是最外层，那时模板还没装配。错误页恰恰最不该依赖可能出错的链路，
所以用内联 HTML + i18n.T，语言从 Accept-Language 猜（拿不到 session）。

蜜罐分流仍在 NotFound 最前面：临时打开 enable_honeypot 实测 /wp-admin
仍返回假 WordPress 登录页（200），普通未知路径返回 404。

二、提问者找回自己的提问

不填邮箱时，唯一能追踪这条提问的东西是提问成功页上那条链接 —— 关掉页面、
链接冲掉了就永久失联。箱主认真答了，提问者永远不知道。这是这类产品最核心的
体验断点，而它不需要账号体系就能解决：

- 成功页把 {domain, id, token} 写进本机 localStorage（最多 30 条，按 domain+id 去重）
- 再访该箱时显示一条不打扰的横条：「这台设备上有 N 条提问记录，其中 M 条已有回答」，
  点「查看」展开列表，每条可直接打开
- 新增 POST /api/v1/ask-status 批量回答「哪些已被回答」：一次 IN 查询，不逐条 N+1

它不能用来枚举：必须同时给出正确 token 才返回 ok=true，而「token 错」「id 不存在」
「不属于该箱主」三种情况的响应完全相同（ok=false / answered=false / excerpt 为空），
无法区分。token 比较走常数时间，单次最多 20 条，限流 30/分钟。用 POST 不用 GET，
因为 token 不能进 URL（会留在浏览器历史、代理日志、Referer 里）。

列表摘要先过 MarkdownPlainText 再按 rune 截断：直接截原文会露出 ![图片](https://...)
这种噪音，一条带图的提问几乎只剩链接。

验证：
- verify_ask_history.py 12/12（含「错误 token / 不存在的 id / 别人的提问」三者
  响应完全一致、缺 CSRF 被拒、超 20 条截断）
- verify_ask_history_ui.mjs 用 CDP 在真实 Chrome 里跑：无记录时提示条隐藏；
  注入记录后显示「1 条，其中 1 条已有回答」；列表渲染、链接带 token、点击展开正常
- 错误页单测 6 项（HTML/不泄露 panic 内容/已写出时不重复写头/语言选择/状态码/转义）

internal/i18n/dict_en.go

@@ -88,41 +88,49 @@ var enDict = map[string]string{
 	"explore.noVotes":      "There are no public polls available right now.",
 
 	// Ask page
-	"ask.scan":              "Scan to ask @%s",
-	"ask.anonymous":         "Anyone can ask anonymously",
-	"ask.registerOnly":      "Only registered users can ask",
-	"ask.nextOpenAt":        "Next opening: %s",
-	"ask.lastCloseAt":       "Last closed: %s",
-	"weekday.0":             "Sun",
-	"weekday.1":             "Mon",
-	"weekday.2":             "Tue",
-	"weekday.3":             "Wed",
-	"weekday.4":             "Thu",
-	"weekday.5":             "Fri",
-	"weekday.6":             "Sat",
-	"ask.pinned":            "Pinned",
-	"ask.share":             "Share this box",
-	"ask.placeholder":       "Write your question here...",
-	"ask.chatPlaceholder":   "Write your chat message here...",
-	"ask.addImage":          "Add image",
-	"ask.private":           "Don't publish after reply",
-	"ask.notify":            "Notify me",
-	"ask.emailPlaceholder":  "Enter your email address",
-	"ask.submit":            "Send question",
-	"ask.chat":              "Start a chat",
-	"ask.chatDisabled":      "Chat is disabled on this box",
-	"ask.chatLimit":         "Message limit: %d",
-	"ask.history":           "Previously answered by @%s",
-	"ask.loginRequired":     "Log in required",
-	"ask.loginRequiredChat": "You need to log in to start a chat",
-	"ask.goLogin":           "Go to login",
-	"ask.needPassword":      "This box requires a password",
-	"ask.needLogin":         "The owner only allows registered users to ask questions. Please log in first.",
-	"ask.pleaseEmail":       "Please enter your email to receive notifications",
-	"ask.generating":        "Generating share card…",
-	"ask.genFailed":         "Failed to generate share card. Please try again later",
-	"ask.networkError":      "Network error",
-	"ask.shareFilename":     "share.png",
+	"ask.scan":                  "Scan to ask @%s",
+	"ask.anonymous":             "Anyone can ask anonymously",
+	"ask.registerOnly":          "Only registered users can ask",
+	"ask.nextOpenAt":            "Next opening: %s",
+	"ask.lastCloseAt":           "Last closed: %s",
+	"weekday.0":                 "Sun",
+	"weekday.1":                 "Mon",
+	"weekday.2":                 "Tue",
+	"weekday.3":                 "Wed",
+	"weekday.4":                 "Thu",
+	"weekday.5":                 "Fri",
+	"weekday.6":                 "Sat",
+	"ask.pinned":                "Pinned",
+	"ask.share":                 "Share this box",
+	"ask.placeholder":           "Write your question here...",
+	"ask.chatPlaceholder":       "Write your chat message here...",
+	"ask.addImage":              "Add image",
+	"ask.private":               "Don't publish after reply",
+	"ask.notify":                "Notify me",
+	"ask.emailPlaceholder":      "Enter your email address",
+	"ask.submit":                "Send question",
+	"ask.chat":                  "Start a chat",
+	"ask.chatDisabled":          "Chat is disabled on this box",
+	"ask.chatLimit":             "Message limit: %d",
+	"ask.history":               "Previously answered by @%s",
+	"askHistory.banner":         "You have {n} question(s) saved on this device",
+	"askHistory.answeredSuffix": ", {m} of them answered",
+	"askHistory.expand":         "View",
+	"askHistory.collapse":       "Hide",
+	"askHistory.answered":       "Answered",
+	"askHistory.pending":        "Awaiting reply",
+	"askHistory.open":           "Open",
+	"askHistory.note":           "Saved only in this browser. Switching devices or clearing browser data will lose them.",
+	"ask.loginRequired":         "Log in required",
+	"ask.loginRequiredChat":     "You need to log in to start a chat",
+	"ask.goLogin":               "Go to login",
+	"ask.needPassword":          "This box requires a password",
+	"ask.needLogin":             "The owner only allows registered users to ask questions. Please log in first.",
+	"ask.pleaseEmail":           "Please enter your email to receive notifications",
+	"ask.generating":            "Generating share card…",
+	"ask.genFailed":             "Failed to generate share card. Please try again later",
+	"ask.networkError":          "Network error",
+	"ask.shareFilename":         "share.png",
 
 	// Question item
 	"qitem.answer":            "Answer",
@@ -846,6 +854,7 @@ var enDict = map[string]string{
 	"vote.err.editClosed":                "Votes that are ended or archived cannot be edited",
 	"vote.err.publishDraftOnly":          "Only draft polls can be published",
 	"vote.err.restrictedPublish":         "Publishing is suspended while this account is under moderation",
+	"feature.stateUnavailable":           "Unable to verify the status of this feature, please try again later",
 	"vote.err.closePublishedOnly":        "Only active polls can be closed",
 	"vote.err.publishTitleRequired":      "Please fill in the poll title before publishing",
 	"vote.err.publishFormFieldsRequired": "Form polls need at least 1 field",
@@ -911,6 +920,12 @@ var enDict = map[string]string{
 	"chat.flash.operated":     "Operation successful",
 	"image.errTooLarge":       "Image is too large, maximum supported size is %d×%d pixels, please compress and re-upload",
 	"internal.errFlash":       "Internal server error, please try again later.",
+	"internal.errBadRequest":  "Invalid request",
+	"error.notFoundTitle":     "Page not found",
+	"error.notFoundDesc":      "There is nothing at this address. The link may be mistyped, or the content has been removed.",
+	"error.internalTitle":     "Something went wrong",
+	"error.internalDesc":      "This request could not be completed. It is usually temporary — try again in a moment.",
+	"error.traceHint":         "Please include this ID when reporting:",
 	"internal.errServer":      "Internal server error",
 	"home.errStats":           "Failed to retrieve statistics",
 	"pixel.errPath":           "Invalid request path",

internal/i18n/dict_ja.go

@@ -88,41 +88,49 @@ var jaDict = map[string]string{
 	"explore.noVotes":      "現在、参加できる公開投票はありません。",
 
 	// 質問ページ
-	"ask.scan":              "QRコードで@%sに質問",
-	"ask.anonymous":         "誰でも匿名で質問できます",
-	"ask.registerOnly":      "登録ユーザーのみ質問できます",
-	"ask.nextOpenAt":        "次回開放：%s",
-	"ask.lastCloseAt":       "前回終了：%s",
-	"weekday.0":             "日",
-	"weekday.1":             "月",
-	"weekday.2":             "火",
-	"weekday.3":             "水",
-	"weekday.4":             "木",
-	"weekday.5":             "金",
-	"weekday.6":             "土",
-	"ask.pinned":            "ピン留め済み",
-	"ask.share":             "質問箱を共有",
-	"ask.placeholder":       "ここに質問を書いてください...",
-	"ask.chatPlaceholder":   "ここにチャットメッセージを書いてください...",
-	"ask.addImage":          "画像を追加",
-	"ask.private":           "返信後に公開しない",
-	"ask.notify":            "通知を受け取る",
-	"ask.emailPlaceholder":  "メールアドレスを入力してください",
-	"ask.submit":            "質問を送信",
-	"ask.chat":              "チャットを開始",
-	"ask.chatDisabled":      "この質問箱ではチャットが無効です",
-	"ask.chatLimit":         "メッセージ上限：%d件",
-	"ask.history":           "@%s が以前回答した質問",
-	"ask.loginRequired":     "ログインが必要",
-	"ask.loginRequiredChat": "チャットを開始するにはログインが必要です",
-	"ask.goLogin":           "ログインへ",
-	"ask.needPassword":      "この質問箱にはパスワードが必要です",
-	"ask.needLogin":         "質問箱の所有者は登録ユーザーのみ質問できるように設定しています。先にログインしてください。",
-	"ask.pleaseEmail":       "通知を受け取るメールアドレスを入力してください",
-	"ask.generating":        "共有カードを生成中…",
-	"ask.genFailed":         "共有カードの生成に失敗しました。しばらくしてからお試しください",
-	"ask.networkError":      "ネットワークエラー",
-	"ask.shareFilename":     "share.png",
+	"ask.scan":                  "QRコードで@%sに質問",
+	"ask.anonymous":             "誰でも匿名で質問できます",
+	"ask.registerOnly":          "登録ユーザーのみ質問できます",
+	"ask.nextOpenAt":            "次回開放：%s",
+	"ask.lastCloseAt":           "前回終了：%s",
+	"weekday.0":                 "日",
+	"weekday.1":                 "月",
+	"weekday.2":                 "火",
+	"weekday.3":                 "水",
+	"weekday.4":                 "木",
+	"weekday.5":                 "金",
+	"weekday.6":                 "土",
+	"ask.pinned":                "ピン留め済み",
+	"ask.share":                 "質問箱を共有",
+	"ask.placeholder":           "ここに質問を書いてください...",
+	"ask.chatPlaceholder":       "ここにチャットメッセージを書いてください...",
+	"ask.addImage":              "画像を追加",
+	"ask.private":               "返信後に公開しない",
+	"ask.notify":                "通知を受け取る",
+	"ask.emailPlaceholder":      "メールアドレスを入力してください",
+	"ask.submit":                "質問を送信",
+	"ask.chat":                  "チャットを開始",
+	"ask.chatDisabled":          "この質問箱ではチャットが無効です",
+	"ask.chatLimit":             "メッセージ上限：%d件",
+	"ask.history":               "@%s が以前回答した質問",
+	"askHistory.banner":         "この端末に {n} 件の質問履歴があります",
+	"askHistory.answeredSuffix": "（うち {m} 件は回答済み）",
+	"askHistory.expand":         "表示",
+	"askHistory.collapse":       "閉じる",
+	"askHistory.answered":       "回答済み",
+	"askHistory.pending":        "回答待ち",
+	"askHistory.open":           "開く",
+	"askHistory.note":           "履歴はこのブラウザにのみ保存されます。端末の変更やブラウザデータの削除で失われます。",
+	"ask.loginRequired":         "ログインが必要",
+	"ask.loginRequiredChat":     "チャットを開始するにはログインが必要です",
+	"ask.goLogin":               "ログインへ",
+	"ask.needPassword":          "この質問箱にはパスワードが必要です",
+	"ask.needLogin":             "質問箱の所有者は登録ユーザーのみ質問できるように設定しています。先にログインしてください。",
+	"ask.pleaseEmail":           "通知を受け取るメールアドレスを入力してください",
+	"ask.generating":            "共有カードを生成中…",
+	"ask.genFailed":             "共有カードの生成に失敗しました。しばらくしてからお試しください",
+	"ask.networkError":          "ネットワークエラー",
+	"ask.shareFilename":         "share.png",
 
 	// 質問アイテム
 	"qitem.answer":            "回答",
@@ -845,6 +853,7 @@ var jaDict = map[string]string{
 	"vote.err.editClosed":                "終了またはアーカイブされた投票は編集できません",
 	"vote.err.publishDraftOnly":          "草稿状態の投票のみ公開できます",
 	"vote.err.restrictedPublish":         "現在はプラットフォームによる措置期間中のため、投票の公開を停止しています",
+	"feature.stateUnavailable":           "機能の状態を確認できませんでした。しばらくしてから再度お試しください",
 	"vote.err.closePublishedOnly":        "進行中の投票のみ終了できます",
 	"vote.err.publishTitleRequired":      "公開前に投票のタイトルを入力してください",
 	"vote.err.publishFormFieldsRequired": "フォーム型投票には最低 1 つの項目が必要です",
@@ -910,6 +919,12 @@ var jaDict = map[string]string{
 	"chat.flash.operated":     "操作が完了しました",
 	"image.errTooLarge":       "画像が大きすぎます。最大%d×%dピクセルまで対応しています。圧縮して再アップロードしてください",
 	"internal.errFlash":       "サーバー内部エラーが発生しました。後でもう一度お試しください。",
+	"internal.errBadRequest":  "リクエストの内容が正しくありません",
+	"error.notFoundTitle":     "ページが見つかりません",
+	"error.notFoundDesc":      "このアドレスにコンテンツはありません。リンクが間違っているか、削除された可能性があります。",
+	"error.internalTitle":     "問題が発生しました",
+	"error.internalDesc":      "このリクエストを完了できませんでした。多くは一時的なものです。しばらくしてから再度お試しください。",
+	"error.traceHint":         "ご報告の際はこの番号を添えてください：",
 	"internal.errServer":      "サーバー内部エラー",
 	"home.errStats":           "統計情報の取得に失敗しました",
 	"pixel.errPath":           "不正なリクエストパス",

internal/i18n/dict_zh_cn.go

@@ -88,41 +88,49 @@ var zhCNDict = map[string]string{
 	"explore.noVotes":      "暂时没有可参与的公开投票。",
 
 	// 提问页
-	"ask.scan":              "扫码向@%s提问",
-	"ask.anonymous":         "谁都可以以匿名的形式提问",
-	"ask.registerOnly":      "仅允许注册用户向TA提问",
-	"ask.nextOpenAt":        "下次开放时间：%s",
-	"ask.lastCloseAt":       "上次关闭时间：%s",
-	"weekday.0":             "周日",
-	"weekday.1":             "周一",
-	"weekday.2":             "周二",
-	"weekday.3":             "周三",
-	"weekday.4":             "周四",
-	"weekday.5":             "周五",
-	"weekday.6":             "周六",
-	"ask.pinned":            "已置顶",
-	"ask.share":             "分享提问箱",
-	"ask.placeholder":       "在此处撰写你的问题...",
-	"ask.chatPlaceholder":   "在此处撰写你的私聊消息...",
-	"ask.addImage":          "添加图片",
-	"ask.private":           "回复后不公开",
-	"ask.notify":            "接收通知",
-	"ask.emailPlaceholder":  "请输入你的邮箱地址",
-	"ask.submit":            "发送提问",
-	"ask.chat":              "发起私聊",
-	"ask.chatDisabled":      "该提问箱未开启私聊",
-	"ask.chatLimit":         "消息上限：%d条",
-	"ask.history":           "@%s 以前回答过的问题",
-	"ask.loginRequired":     "需要登录",
-	"ask.loginRequiredChat": "发起私聊需要登录账号",
-	"ask.goLogin":           "去登录",
-	"ask.needPassword":      "此提问箱需要密码",
-	"ask.needLogin":         "提问箱的主人设置了仅注册用户才能提问，你需要先登录才能向他提问。",
-	"ask.pleaseEmail":       "请填写接收通知的邮箱地址",
-	"ask.generating":        "正在生成分享图…",
-	"ask.genFailed":         "生成分享图失败，请稍后重试",
-	"ask.networkError":      "网络错误",
-	"ask.shareFilename":     "share.png",
+	"ask.scan":                  "扫码向@%s提问",
+	"ask.anonymous":             "谁都可以以匿名的形式提问",
+	"ask.registerOnly":          "仅允许注册用户向TA提问",
+	"ask.nextOpenAt":            "下次开放时间：%s",
+	"ask.lastCloseAt":           "上次关闭时间：%s",
+	"weekday.0":                 "周日",
+	"weekday.1":                 "周一",
+	"weekday.2":                 "周二",
+	"weekday.3":                 "周三",
+	"weekday.4":                 "周四",
+	"weekday.5":                 "周五",
+	"weekday.6":                 "周六",
+	"ask.pinned":                "已置顶",
+	"ask.share":                 "分享提问箱",
+	"ask.placeholder":           "在此处撰写你的问题...",
+	"ask.chatPlaceholder":       "在此处撰写你的私聊消息...",
+	"ask.addImage":              "添加图片",
+	"ask.private":               "回复后不公开",
+	"ask.notify":                "接收通知",
+	"ask.emailPlaceholder":      "请输入你的邮箱地址",
+	"ask.submit":                "发送提问",
+	"ask.chat":                  "发起私聊",
+	"ask.chatDisabled":          "该提问箱未开启私聊",
+	"ask.chatLimit":             "消息上限：%d条",
+	"ask.history":               "@%s 以前回答过的问题",
+	"askHistory.banner":         "这台设备上有 {n} 条提问记录",
+	"askHistory.answeredSuffix": "，其中 {m} 条已有回答",
+	"askHistory.expand":         "查看",
+	"askHistory.collapse":       "收起",
+	"askHistory.answered":       "已有回答",
+	"askHistory.pending":        "等待回答",
+	"askHistory.open":           "打开",
+	"askHistory.note":           "记录只保存在这台设备的浏览器里，换设备或清除浏览器数据后会丢失。",
+	"ask.loginRequired":         "需要登录",
+	"ask.loginRequiredChat":     "发起私聊需要登录账号",
+	"ask.goLogin":               "去登录",
+	"ask.needPassword":          "此提问箱需要密码",
+	"ask.needLogin":             "提问箱的主人设置了仅注册用户才能提问，你需要先登录才能向他提问。",
+	"ask.pleaseEmail":           "请填写接收通知的邮箱地址",
+	"ask.generating":            "正在生成分享图…",
+	"ask.genFailed":             "生成分享图失败，请稍后重试",
+	"ask.networkError":          "网络错误",
+	"ask.shareFilename":         "share.png",
 
 	// 问题条目
 	"qitem.answer":            "回答",
@@ -846,6 +854,7 @@ var zhCNDict = map[string]string{
 	"vote.err.editClosed":                "已结束或归档的投票不允许编辑",
 	"vote.err.publishDraftOnly":          "只有草稿状态的投票可以发布",
 	"vote.err.restrictedPublish":         "当前处于平台处置期，已暂停发布投票",
+	"feature.stateUnavailable":           "暂时无法确认该功能的状态，请稍后重试",
 	"vote.err.closePublishedOnly":        "只有进行中的投票可以结束",
 	"vote.err.publishTitleRequired":      "请先填写投票标题再发布",
 	"vote.err.publishFormFieldsRequired": "表单类型投票至少需要 1 个字段",
@@ -923,6 +932,12 @@ var zhCNDict = map[string]string{
 	"chat.flash.operated":     "操作成功",
 	"image.errTooLarge":       "图片尺寸过大，最大支持 %d×%d 像素，请压缩后重新上传",
 	"internal.errFlash":       "服务内部错误，请稍后重试。",
+	"internal.errBadRequest":  "请求参数不正确",
+	"error.notFoundTitle":     "页面不存在",
+	"error.notFoundDesc":      "这个地址没有内容，可能是链接输错了，或者内容已经被删除。",
+	"error.internalTitle":     "服务出了点问题",
+	"error.internalDesc":      "这次请求没能完成，通常是临时的。稍后重试一般就好了。",
+	"error.traceHint":         "反馈时请带上这个编号：",
 	"internal.errServer":      "服务器内部错误",
 	"home.errStats":           "获取统计信息失败",
 	"pixel.errPath":           "非法的请求路径",

internal/i18n/dict_zh_tw.go

@@ -88,41 +88,49 @@ var zhTWDict = map[string]string{
 	"explore.noVotes":      "暫時沒有可參與的公開投票。",
 
 	// 提問頁
-	"ask.scan":              "掃碼向@%s提問",
-	"ask.anonymous":         "誰都可以以匿名的方式提問",
-	"ask.registerOnly":      "僅允許註冊使用者向TA提問",
-	"ask.nextOpenAt":        "下次開放時間：%s",
-	"ask.lastCloseAt":       "上次關閉時間：%s",
-	"weekday.0":             "週日",
-	"weekday.1":             "週一",
-	"weekday.2":             "週二",
-	"weekday.3":             "週三",
-	"weekday.4":             "週四",
-	"weekday.5":             "週五",
-	"weekday.6":             "週六",
-	"ask.pinned":            "已置頂",
-	"ask.share":             "分享提問箱",
-	"ask.placeholder":       "在此處撰寫你的問題...",
-	"ask.chatPlaceholder":   "在此處撰寫你的私聊訊息...",
-	"ask.addImage":          "新增圖片",
-	"ask.private":           "回覆後不公開",
-	"ask.notify":            "接收通知",
-	"ask.emailPlaceholder":  "請輸入你的信箱地址",
-	"ask.submit":            "傳送提問",
-	"ask.chat":              "發起私聊",
-	"ask.chatDisabled":      "該提問箱未開啟私聊",
-	"ask.chatLimit":         "訊息上限：%d則",
-	"ask.history":           "@%s 以前回答過的問題",
-	"ask.loginRequired":     "需要登入",
-	"ask.loginRequiredChat": "發起私聊需要登入帳號",
-	"ask.goLogin":           "去登入",
-	"ask.needPassword":      "此提問箱需要密碼",
-	"ask.needLogin":         "提問箱的主人設定了僅註冊使用者才能提問，你需要先登入才能向他提問。",
-	"ask.pleaseEmail":       "請填寫接收通知的信箱地址",
-	"ask.generating":        "正在產生分享圖…",
-	"ask.genFailed":         "產生分享圖失敗，請稍後重試",
-	"ask.networkError":      "網路錯誤",
-	"ask.shareFilename":     "share.png",
+	"ask.scan":                  "掃碼向@%s提問",
+	"ask.anonymous":             "誰都可以以匿名的方式提問",
+	"ask.registerOnly":          "僅允許註冊使用者向TA提問",
+	"ask.nextOpenAt":            "下次開放時間：%s",
+	"ask.lastCloseAt":           "上次關閉時間：%s",
+	"weekday.0":                 "週日",
+	"weekday.1":                 "週一",
+	"weekday.2":                 "週二",
+	"weekday.3":                 "週三",
+	"weekday.4":                 "週四",
+	"weekday.5":                 "週五",
+	"weekday.6":                 "週六",
+	"ask.pinned":                "已置頂",
+	"ask.share":                 "分享提問箱",
+	"ask.placeholder":           "在此處撰寫你的問題...",
+	"ask.chatPlaceholder":       "在此處撰寫你的私聊訊息...",
+	"ask.addImage":              "新增圖片",
+	"ask.private":               "回覆後不公開",
+	"ask.notify":                "接收通知",
+	"ask.emailPlaceholder":      "請輸入你的信箱地址",
+	"ask.submit":                "傳送提問",
+	"ask.chat":                  "發起私聊",
+	"ask.chatDisabled":          "該提問箱未開啟私聊",
+	"ask.chatLimit":             "訊息上限：%d則",
+	"ask.history":               "@%s 以前回答過的問題",
+	"askHistory.banner":         "這台裝置上有 {n} 筆提問紀錄",
+	"askHistory.answeredSuffix": "，其中 {m} 筆已有回答",
+	"askHistory.expand":         "查看",
+	"askHistory.collapse":       "收合",
+	"askHistory.answered":       "已有回答",
+	"askHistory.pending":        "等待回答",
+	"askHistory.open":           "開啟",
+	"askHistory.note":           "紀錄只保存在這台裝置的瀏覽器裡，換裝置或清除瀏覽器資料後會遺失。",
+	"ask.loginRequired":         "需要登入",
+	"ask.loginRequiredChat":     "發起私聊需要登入帳號",
+	"ask.goLogin":               "去登入",
+	"ask.needPassword":          "此提問箱需要密碼",
+	"ask.needLogin":             "提問箱的主人設定了僅註冊使用者才能提問，你需要先登入才能向他提問。",
+	"ask.pleaseEmail":           "請填寫接收通知的信箱地址",
+	"ask.generating":            "正在產生分享圖…",
+	"ask.genFailed":             "產生分享圖失敗，請稍後重試",
+	"ask.networkError":          "網路錯誤",
+	"ask.shareFilename":         "share.png",
 
 	// 問題條目
 	"qitem.answer":            "回答",
@@ -845,6 +853,7 @@ var zhTWDict = map[string]string{
 	"vote.err.editClosed":                "已結束或歸檔的投票不允許編輯",
 	"vote.err.publishDraftOnly":          "只有草稿狀態的投票可以發布",
 	"vote.err.restrictedPublish":         "當前處於平台處置期，已暫停發布投票",
+	"feature.stateUnavailable":           "暫時無法確認該功能的狀態，請稍後重試",
 	"vote.err.closePublishedOnly":        "只有進行中的投票可以結束",
 	"vote.err.publishTitleRequired":      "請先填寫投票標題再發布",
 	"vote.err.publishFormFieldsRequired": "表單類型投票至少需要 1 個欄位",
@@ -910,6 +919,12 @@ var zhTWDict = map[string]string{
 	"chat.flash.operated":     "操作成功",
 	"image.errTooLarge":       "圖片尺寸過大，最大支援 %d×%d 像素，請壓縮後重新上傳",
 	"internal.errFlash":       "服務內部錯誤，請稍後重試。",
+	"internal.errBadRequest":  "請求參數不正確",
+	"error.notFoundTitle":     "頁面不存在",
+	"error.notFoundDesc":      "這個位址沒有內容，可能是連結輸入錯誤，或者內容已經被刪除。",
+	"error.internalTitle":     "服務出了點問題",
+	"error.internalDesc":      "這次請求沒能完成，通常是暫時的。稍後重試一般就好了。",
+	"error.traceHint":         "回報時請帶上這個編號：",
 	"internal.errServer":      "伺服器內部錯誤",
 	"home.errStats":           "獲取統計資訊失敗",
 	"pixel.errPath":           "非法的請求路徑",

internal/route/errorpage.go

@@ -0,0 +1,172 @@
+// Copyright 2026 tamakyi. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package route
+
+import (
+	"fmt"
+	"net/http"
+	"runtime/debug"
+	"strings"
+
+	"github.com/flamego/flamego"
+	"github.com/sirupsen/logrus"
+	"go.opentelemetry.io/otel/trace"
+
+	"github.com/tamakyi/TamaBox/internal/i18n"
+	"github.com/tamakyi/TamaBox/internal/shared"
+)
+
+// recoveryMiddleware 替代 flamego.Recovery()，把 panic 渲染成 HTML 500 页。
+//
+// 为什么不用框架自带的：flamego.Recovery() 直接写纯文本 "Internal Server Error"，
+// 用户看到的是白底黑字的两行英文，地址栏还停在出错的 URL 上 ——
+// 既不知道发生了什么，也没有回去的入口，更没法把这次错误的编号报给我们。
+func recoveryMiddleware() flamego.Handler {
+	return func(ctx flamego.Context) {
+		defer func() {
+			if r := recover(); r != nil {
+				// 带栈：没有栈的 panic 日志几乎无法定位。
+				logrus.WithContext(ctx.Request().Context()).
+					Errorf("panic recovered: %v\n%s", r, debug.Stack())
+
+				if ctx.ResponseWriter().Written() {
+					// 头已经发出去了，没法再改状态码，只能让连接断在这里。
+					return
+				}
+				writeErrorPage(ctx, http.StatusInternalServerError, "error.internalTitle", "error.internalDesc")
+			}
+		}()
+		ctx.Next()
+	}
+}
+
+// writeErrorPage 输出不依赖模板系统的完整错误页。
+//
+// 为什么不用模板：这两个页面出现在两处「拿不到模板」的地方 ——
+// NotFound 处理器不在组级中间件链里（template.Templater 与 Contexter 都挂在组级，
+// 包括 session 与 CSRF），而 recovery 中间件挂在最外层，那时模板还没装配。
+// 错误页恰恰是最不该依赖出错链路的页面，所以这里用内联 HTML + i18n.T。
+func writeErrorPage(ctx flamego.Context, status int, titleKey, descKey string) {
+	lang := pickErrorPageLang(ctx.Request().Request)
+	title := i18n.T(lang, titleKey)
+	desc := i18n.T(lang, descKey)
+	home := i18n.T(lang, "deactivated.backHome")
+	hint := i18n.T(lang, "error.traceHint")
+
+	traceID := ""
+	if span := trace.SpanFromContext(ctx.Request().Context()); span.SpanContext().TraceID().IsValid() {
+		traceID = span.SpanContext().TraceID().String()
+	}
+
+	body := fmt.Sprintf(`<!DOCTYPE html>
+<html lang="%s"><head><meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1">
+<meta name="robots" content="noindex">
+<title>%s</title>
+<style>
+  :root { color-scheme: light dark; }
+  * { box-sizing: border-box; }
+  body {
+    margin: 0; min-height: 100vh; display: flex; align-items: center; justify-content: center;
+    padding: 24px; background: #f7f7f8; color: #1f2328;
+    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB",
+                 "Microsoft YaHei", sans-serif; line-height: 1.7;
+  }
+  .card {
+    width: 100%%; max-width: 30rem; padding: 2rem 1.75rem; text-align: center;
+    background: #fff; border-radius: 12px; box-shadow: 0 1px 3px rgba(0,0,0,.08), 0 8px 24px rgba(0,0,0,.04);
+  }
+  h1 { font-size: 1.35rem; margin: 0 0 .75rem; font-weight: 600; }
+  p { margin: 0; color: #59636e; }
+  .hint { margin-top: 1rem; font-size: .8125rem; color: #818b98; }
+  code { background: #eceef0; padding: .1rem .35rem; border-radius: 4px; font-size: .8125rem; }
+  .actions { margin-top: 1.75rem; }
+  a.btn {
+    display: inline-block; padding: .55rem 1.25rem; border-radius: 6px;
+    background: #1f6feb; color: #fff; text-decoration: none; font-size: .9375rem;
+  }
+  a.btn:hover { background: #1a5fd0; }
+  @media (prefers-color-scheme: dark) {
+    body { background: #16181a; color: #e6edf3; }
+    .card { background: #1f2225; box-shadow: none; border: 1px solid #2c3136; }
+    p { color: #9aa4af; }
+    .hint { color: #7d8792; }
+    code { background: #2c3136; }
+  }
+</style></head>
+<body><div class="card">
+  <h1>%s</h1>
+  <p>%s</p>
+  %s
+  <div class="actions"><a class="btn" href="/">%s</a></div>
+</div></body></html>`,
+		htmlLang(lang), esc(title), esc(title), esc(desc),
+		func() string {
+			if traceID == "" {
+				return ""
+			}
+			return `<p class="hint">` + esc(hint) + ` <code>` + esc(traceID) + `</code></p>`
+		}(),
+		esc(home),
+	)
+
+	ctx.ResponseWriter().Header().Set("Content-Type", "text/html; charset=utf-8")
+	ctx.ResponseWriter().Header().Set("X-Content-Type-Options", "nosniff")
+	// 错误页不缓存：修好之后用户刷新应该立刻拿到正常页面。
+	ctx.ResponseWriter().Header().Set("Cache-Control", "no-store")
+	ctx.ResponseWriter().WriteHeader(status)
+	_, _ = ctx.ResponseWriter().Write([]byte(body))
+}
+
+// pickErrorPageLang 选错误页语言。
+//
+// 这里拿不到 session（sessioner 是组级中间件，NotFound 不经过它），
+// 所以只能从 Accept-Language 猜一个，猜不到就用站点默认语言。
+func pickErrorPageLang(r *http.Request) string {
+	def := i18n.Resolve(shared.App.Lang())
+	header := strings.ToLower(r.Header.Get("Accept-Language"))
+	if header == "" {
+		return def
+	}
+
+	// 按声明顺序取第一个能识别的语言偏好（q 值排序这里不精确处理：
+	// 错误页的语言不需要那么讲究，按出现顺序取第一个命中的即可）。
+	for _, part := range strings.Split(header, ",") {
+		tag := strings.TrimSpace(strings.SplitN(part, ";", 2)[0])
+		switch {
+		case strings.HasPrefix(tag, "zh-tw"), strings.HasPrefix(tag, "zh-hk"),
+			strings.HasPrefix(tag, "zh-hant"):
+			return i18n.Resolve("zh-TW")
+		case strings.HasPrefix(tag, "zh"):
+			return i18n.Resolve("zh-CN")
+		case strings.HasPrefix(tag, "ja"):
+			return i18n.Resolve("ja")
+		case strings.HasPrefix(tag, "en"):
+			return i18n.Resolve("en")
+		}
+	}
+	return def
+}
+
+// htmlLang 把内部语言代码转成 <html lang> 该用的 BCP 47 值。
+func htmlLang(lang string) string {
+	switch lang {
+	case "zh-CN":
+		return "zh-CN"
+	case "zh-TW":
+		return "zh-Hant"
+	case "ja":
+		return "ja"
+	default:
+		return "en"
+	}
+}
+
+// esc 对极少数字符做转义。这里的内容全部来自字典（不是用户输入），
+// 但仍然转义一次 —— 字典里出现引号或 & 时不能把页面结构弄坏。
+func esc(s string) string {
+	r := strings.NewReplacer("&", "&amp;", "<", "&lt;", ">", "&gt;", `"`, "&quot;", "'", "&#39;")
+	return r.Replace(s)
+}

internal/route/errorpage_test.go

@@ -0,0 +1,126 @@
+// Copyright 2026 tamakyi. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package route
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/flamego/flamego"
+	"github.com/stretchr/testify/require"
+)
+
+// TestRecoveryMiddlewareRendersHTML 锁住 panic 的对外表现。
+//
+// 改动前用的是 flamego.Recovery()：它直接写纯文本 "Internal Server Error"，
+// 用户看到白底黑字两行英文，没有返回入口，也拿不到可以报给我们的编号。
+func TestRecoveryMiddlewareRendersHTML(t *testing.T) {
+	f := flamego.New()
+	f.Use(recoveryMiddleware())
+	f.Get("/boom", func() {
+		panic("boom")
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/boom", nil)
+	resp := httptest.NewRecorder()
+	f.ServeHTTP(resp, req)
+
+	require.Equal(t, http.StatusInternalServerError, resp.Code)
+	require.True(t, strings.HasPrefix(resp.Header().Get("Content-Type"), "text/html"),
+		"必须是 HTML，不能退回纯文本")
+	require.Equal(t, "no-store", resp.Header().Get("Cache-Control"))
+
+	body := resp.Body.String()
+	require.Contains(t, body, "<!DOCTYPE html>")
+	// 中文环境（default lang）下应给出可读文案与返回入口
+	require.Contains(t, body, "服务出了点问题")
+	require.Contains(t, body, `href="/"`, "错误页必须有返回首页的入口")
+	require.NotContains(t, body, "boom", "不能把 panic 内容暴露给用户")
+}
+
+// TestRecoveryMiddlewareDoesNotDoubleWrite 响应已写出时不能再写头。
+//
+// 场景：handler 先写了一部分内容再 panic。这时 HTTP 头已经发出去了，
+// 再 WriteHeader 会被 net/http 忽略（并打 superfluous 警告），
+// 强行写还会把已经发出去的响应体盖掉。
+func TestRecoveryMiddlewareDoesNotDoubleWrite(t *testing.T) {
+	f := flamego.New()
+	f.Use(recoveryMiddleware())
+	f.Get("/half", func(ctx flamego.Context) {
+		_, _ = ctx.ResponseWriter().Write([]byte("partial"))
+		panic("boom after write")
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/half", nil)
+	resp := httptest.NewRecorder()
+	f.ServeHTTP(resp, req)
+
+	require.Equal(t, http.StatusOK, resp.Code, "头已发出，状态码不能变")
+	require.Equal(t, "partial", resp.Body.String(), "不能把已写出的内容覆盖掉")
+}
+
+// TestPickErrorPageLang 错误页语言只能靠 Accept-Language 猜
+// （sessioner 是组级中间件，NotFound 不经过它）。
+func TestPickErrorPageLang(t *testing.T) {
+	cases := []struct {
+		name   string
+		header string
+		want   string
+	}{
+		{"空 header 用站点默认", "", ""},
+		{"英文", "en-US,en;q=0.9", "en"},
+		{"日文", "ja-JP,ja;q=0.9", "ja"},
+		{"繁体", "zh-TW,zh;q=0.9", "zh-TW"},
+		{"zh-Hant 也算繁体", "zh-Hant", "zh-TW"},
+		{"简体", "zh-CN,zh;q=0.9", "zh-CN"},
+		// 浏览器常把首选语言排在前面，这里按出现顺序取第一个能识别的
+		{"首选英文后跟日文", "en-GB,en;q=0.9,ja;q=0.5", "en"},
+		{"无法识别时回退默认", "de-DE,fr;q=0.8", ""},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			req := httptest.NewRequest(http.MethodGet, "/nope", nil)
+			if c.header != "" {
+				req.Header.Set("Accept-Language", c.header)
+			}
+			got := pickErrorPageLang(req)
+			if c.want == "" {
+				// 回退到站点默认语言，不是空串
+				require.NotEmpty(t, got)
+				return
+			}
+			require.Equal(t, c.want, got)
+		})
+	}
+}
+
+// TestWriteErrorPageStatusCodes 404 与 500 各自的状态码与 noindex。
+func TestWriteErrorPageStatusCodes(t *testing.T) {
+	for _, status := range []int{http.StatusNotFound, http.StatusInternalServerError} {
+		f := flamego.New()
+		f.Get("/x", func(ctx flamego.Context) {
+			writeErrorPage(ctx, status, "error.notFoundTitle", "error.notFoundDesc")
+		})
+
+		req := httptest.NewRequest(http.MethodGet, "/x", nil)
+		resp := httptest.NewRecorder()
+		f.ServeHTTP(resp, req)
+
+		require.Equal(t, status, resp.Code)
+		require.Contains(t, resp.Body.String(), `name="robots" content="noindex"`,
+			"错误页不该被搜索引擎收录")
+	}
+}
+
+// TestEscErrorPageText 字典文本里出现引号/尖括号时不能把页面结构弄坏。
+func TestEscErrorPageText(t *testing.T) {
+	require.Equal(t, "a&quot;b", esc(`a"b`))
+	require.Equal(t, "&lt;script&gt;", esc("<script>"))
+	require.Equal(t, "a&amp;b", esc("a&b"))
+	require.Equal(t, "&#39;x&#39;", esc("'x'"))
+}

internal/route/route.go

@@ -193,7 +193,7 @@ func New() *flamego.Flame {
 	f := flamego.New()
 	// 访问日志放在 Recovery 外层：panic 被兜成 500 后仍能记到状态码。
 	f.Use(accessLogMiddleware())
-	f.Use(flamego.Recovery())
+	f.Use(recoveryMiddleware())
 
 	if conf.App.Production {
 		flamego.SetEnv(flamego.EnvTypeProd)
@@ -563,6 +563,10 @@ func New() *flamego.Flame {
 			f.Get("/explore/random", rateLimitMiddleware(60, 1*time.Minute), user.RandomRecommend)
 			// 首页"提问箱信息统计"公开接口（服务端 30 分钟缓存），供前端定时刷新
 			f.Get("/site-stats", rateLimitMiddleware(60, 1*time.Minute), route.SiteStatsAPI)
+			// 提问者「找回自己的提问」：浏览器里存着 {id, token}，回访时批量问一次
+			// 哪些已被回答。必须同时给出正确 token 才返回有效信息，无法用于枚举。
+			// 用 POST 而不是 GET：token 不能进 URL（会留在浏览器历史、代理日志、Referer 里）。
+			f.Post("/ask-status", rateLimitMiddleware(30, 1*time.Minute), question.AskStatusAPI)
 		}, context.APIEndpoint)
 	},
 		cacheHandler,
@@ -624,7 +628,14 @@ func New() *flamego.Flame {
 		if ip := shared.LimitKey(shared.ResolveClientIP(ctx.Request().Request)); ip != "" {
 			ab.Record(ip, ctx.Request().URL.Path, autoban.KindNotFound)
 		}
-		ctx.Redirect("/")
+
+		// 真 404：渲染错误页并写 404 状态码。
+		//
+		// 原来这里是 ctx.Redirect("/")。对用户来说那是「点了链接，地址栏跳到首页，
+		// 却什么都没提示」—— 分不清是链接坏了还是自己点错了；对搜索引擎是软 404，
+		// 失效链接会被当成有效页面收进索引，一直占着抓取预算。
+		// 蜜罐分流仍在最前面，这里只处理「确实不存在的普通路径」。
+		writeErrorPage(ctx, http.StatusNotFound, "error.notFoundTitle", "error.notFoundDesc")
 	})
 
 	return f