feat: 管理端板块管理与旧版数据导入，补充部署运营文档

- 新增管理端板块管理页面与后端接口（admin_board）
- 新增旧版数据导入：legacyimport 服务、导入面板、importusers 命令行工具
- 聊天用户卡片、板块图标等 UI 组件与界面优化
- 补充 about/公告/1Panel 部署等文档
- gitignore 排除 dist/ 构建产物与 .agents/ 本地工具目录

backend/service/operations_mail.go

@@ -392,7 +392,7 @@ func (o *Operations) SendCode(email, purpose, ip string) (int, error) {
 			return 0, nil
 		}
 	}
-	code := randomID()
+	code := randomCode()
 	hash := counterKey(email + ":" + purpose + ":" + code)
 	e = o.db.Transaction(func(tx *gorm.DB) error {
 		if e := tx.Create(&model.EmailChallenge{Hash: hash, Email: email, Purpose: purpose, ExpiresAt: time.Now().Add(15 * time.Minute)}).Error; e != nil {
@@ -402,17 +402,60 @@ func (o *Operations) SendCode(email, purpose, ip string) (int, error) {
 	})
 	return 0, e
 }
+const (
+	codeVerifyMaxAttempts = 5
+	codeVerifyWindow      = 15 * 60 // 秒，与验证码有效期一致
+)
+
+// CodeThrottleError 表示验证码校验失败次数超限，携带需等待的秒数。
+type CodeThrottleError struct{ Wait int }
+
+func (e *CodeThrottleError) Error() string {
+	return fmt.Sprintf("验证码错误次数过多，请 %d 秒后重试", e.Wait)
+}
+
 func (o *Operations) ConsumeCode(email, purpose, code string) error {
-	r := o.db.Model(&model.EmailChallenge{}).Where("hash = ? AND used = false AND expires_at > ?", counterKey(strings.ToLower(strings.TrimSpace(email))+":"+purpose+":"+code), time.Now()).Update("used", true)
+	email = strings.ToLower(strings.TrimSpace(email))
+	failKey := "verifyfail:" + purpose + ":" + email
+
+	// 失败次数限流：窗口内错误次数超限则拒绝，防止 6 位数字码被暴力枚举。
+	if wait, e := o.verifyFailWait(failKey); e != nil {
+		return e
+	} else if wait > 0 {
+		return &CodeThrottleError{Wait: wait}
+	}
+
+	r := o.db.Model(&model.EmailChallenge{}).Where("hash = ? AND used = false AND expires_at > ?", counterKey(email+":"+purpose+":"+code), time.Now()).Update("used", true)
 	if r.Error != nil {
 		return r.Error
 	}
 	if r.RowsAffected != 1 {
+		if _, e := o.Quota(failKey, codeVerifyMaxAttempts, codeVerifyWindow); e != nil {
+			return e
+		}
 		return fmt.Errorf("验证码无效或已过期")
 	}
+	// 校验成功，清除失败计数。
+	o.db.Delete(&model.ActionCounter{}, "key = ?", counterKey(failKey))
 	return nil
 }
 
+// verifyFailWait 读取当前失败计数，若已达上限返回需等待的秒数，不修改计数。
+func (o *Operations) verifyFailWait(key string) (int, error) {
+	var c model.ActionCounter
+	e := o.db.First(&c, "key = ?", counterKey(key)).Error
+	if e != nil {
+		if errors.Is(e, gorm.ErrRecordNotFound) {
+			return 0, nil
+		}
+		return 0, e
+	}
+	if time.Now().Before(c.ExpiresAt) && c.Count >= codeVerifyMaxAttempts {
+		return int(time.Until(c.ExpiresAt).Seconds()) + 1, nil
+	}
+	return 0, nil
+}
+
 // Probe merged drafts so partial API updates cannot bypass activation validation.
 func (o *Operations) ProbeBeforeSave(ctx context.Context, name string, raw json.RawMessage, clear []string) error {
 	v, _, _, e := o.draft(o.db, name, raw, clear)