fix: harden token auth error handling to prevent info leakage

- Create model/errors.go to centralize all sentinel errors
- ValidateAccessToken now returns error to distinguish DB failures
- ValidateUserToken uses unified ErrTokenInvalid for all auth failures
  (expired/exhausted/disabled/not-found) to prevent token enumeration
- authHelper and TokenAuthReadOnly use i18n messages instead of
  hardcoded Chinese strings
- All err.Error() removed from user-facing responses; DB errors logged
  server-side and return generic "contact admin" message (HTTP 500)
- Migrate ErrRedeemFailed, ErrTwoFANotEnabled to model/errors.go

i18n/keys.go

@@ -28,6 +28,18 @@ const (
 	MsgBatchTooMany      = "common.batch_too_many"
 )
 
+// Auth middleware messages
+const (
+	MsgAuthNotLoggedIn           = "auth.not_logged_in"
+	MsgAuthAccessTokenInvalid    = "auth.access_token_invalid"
+	MsgAuthUserInfoInvalid       = "auth.user_info_invalid"
+	MsgAuthUserIdNotProvided     = "auth.user_id_not_provided"
+	MsgAuthUserIdFormatError     = "auth.user_id_format_error"
+	MsgAuthUserIdMismatch        = "auth.user_id_mismatch"
+	MsgAuthUserBanned            = "auth.user_banned"
+	MsgAuthInsufficientPrivilege = "auth.insufficient_privilege"
+)
+
 // Token related messages
 const (
 	MsgTokenNameTooLong          = "token.name_too_long"

i18n/locales/en.yaml

@@ -23,6 +23,16 @@ common.already_exists: "Already exists"
 common.name_cannot_be_empty: "Name cannot be empty"
 common.batch_too_many: "Too many items in batch request, maximum is {{.Max}}"
 
+# Auth middleware messages
+auth.not_logged_in: "Unauthorized, not logged in and no access token provided"
+auth.access_token_invalid: "Unauthorized, invalid access token"
+auth.user_info_invalid: "Unauthorized, invalid user info"
+auth.user_id_not_provided: "Unauthorized, New-Api-User header not provided"
+auth.user_id_format_error: "Unauthorized, New-Api-User header format error"
+auth.user_id_mismatch: "Unauthorized, New-Api-User does not match logged in user"
+auth.user_banned: "User has been banned"
+auth.insufficient_privilege: "Unauthorized, insufficient privileges"
+
 # Token messages
 token.name_too_long: "Token name is too long"
 token.quota_negative: "Quota value cannot be negative"

i18n/locales/zh-CN.yaml

@@ -24,6 +24,16 @@ common.already_exists: "已存在"
 common.name_cannot_be_empty: "名称不能为空"
 common.batch_too_many: "批量请求数量过多，最多 {{.Max}} 条"
 
+# Auth middleware messages
+auth.not_logged_in: "无权进行此操作，未登录且未提供 access token"
+auth.access_token_invalid: "无权进行此操作，access token 无效"
+auth.user_info_invalid: "无权进行此操作，用户信息无效"
+auth.user_id_not_provided: "无权进行此操作，未提供 New-Api-User"
+auth.user_id_format_error: "无权进行此操作，New-Api-User 格式错误"
+auth.user_id_mismatch: "无权进行此操作，New-Api-User 与登录用户不匹配"
+auth.user_banned: "用户已被封禁"
+auth.insufficient_privilege: "无权进行此操作，权限不足"
+
 # Token messages
 token.name_too_long: "令牌名称过长"
 token.quota_negative: "额度值不能为负数"

i18n/locales/zh-TW.yaml

@@ -24,6 +24,16 @@ common.already_exists: "已存在"
 common.name_cannot_be_empty: "名稱不能為空"
 common.batch_too_many: "批次請求數量過多，最多 {{.Max}} 條"
 
+# Auth middleware messages
+auth.not_logged_in: "無權進行此操作，未登入且未提供 access token"
+auth.access_token_invalid: "無權進行此操作，access token 無效"
+auth.user_info_invalid: "無權進行此操作，使用者資訊無效"
+auth.user_id_not_provided: "無權進行此操作，未提供 New-Api-User"
+auth.user_id_format_error: "無權進行此操作，New-Api-User 格式錯誤"
+auth.user_id_mismatch: "無權進行此操作，New-Api-User 與登入使用者不匹配"
+auth.user_banned: "使用者已被封禁"
+auth.insufficient_privilege: "無權進行此操作，權限不足"
+
 # Token messages
 token.name_too_long: "令牌名稱過長"
 token.quota_negative: "額度值不能為負數"