feat: improve model price error UX with role-aware messages and cleaner UI

- Backend: differentiate error messages for admin vs regular users in price.go
- Backend: include error_code in channel test response for structured error handling
- Frontend: render model_price_error as a styled card in Playground with admin nav button
- Frontend: show inline error details and settings link in channel test modal
- Frontend: parse error codes from both SSE and non-streaming API responses
- i18n: remove redundant "Settings" suffix from setting tab translations (en/fr/ru/ja/vi)
- i18n: update "Group & Model Pricing" translations across all locales

relay/helper/price.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/QuantumNous/new-api/common"
 	"github.com/QuantumNous/new-api/logger"
+	"github.com/QuantumNous/new-api/model"
 	relaycommon "github.com/QuantumNous/new-api/relay/common"
 	"github.com/QuantumNous/new-api/setting/operation_setting"
 	"github.com/QuantumNous/new-api/setting/ratio_setting"
@@ -13,6 +14,21 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
+func modelPriceNotConfiguredError(modelName string, userId int) error {
+	if model.IsAdmin(userId) {
+		return fmt.Errorf(
+			"模型 %s 的价格未配置。请前往「系统设置 → 运营设置」开启自用模式，或在「系统设置 → 分组与模型定价设置」中为该模型配置价格；"+
+				"Model %s price not configured. Go to System Settings → Operation Settings to enable self-use mode, or configure the model price in System Settings → Group & Model Pricing.",
+			modelName, modelName,
+		)
+	}
+	return fmt.Errorf(
+		"模型 %s 的价格尚未由管理员配置，暂时无法使用，请联系站点管理员开启该模型；"+
+			"Model %s has not been priced by the administrator yet. Please contact the site administrator to enable this model.",
+		modelName, modelName,
+	)
+}
+
 // https://docs.claude.com/en/docs/build-with-claude/prompt-caching#1-hour-cache-duration
 const claudeCacheCreation1hMultiplier = 6 / 3.75
 
@@ -75,7 +91,7 @@ func ModelPriceHelper(c *gin.Context, info *relaycommon.RelayInfo, promptTokens
 				acceptUnsetRatio = true
 			}
 			if !acceptUnsetRatio {
-				return types.PriceData{}, fmt.Errorf("模型 %s 倍率或价格未配置，请联系管理员设置或开始自用模式；Model %s ratio or price not set, please set or start self-use mode", matchName, matchName)
+				return types.PriceData{}, modelPriceNotConfiguredError(matchName, info.UserId)
 			}
 		}
 		completionRatio = ratio_setting.GetCompletionRatio(info.OriginModelName)
@@ -161,7 +177,7 @@ func ModelPriceHelperPerCall(c *gin.Context, info *relaycommon.RelayInfo) (types
 				acceptUnsetRatio = true
 			}
 			if !ratioSuccess && !acceptUnsetRatio {
-				return types.PriceData{}, fmt.Errorf("模型 %s 倍率或价格未配置，请联系管理员设置或开始自用模式；Model %s ratio or price not set, please set or start self-use mode", matchName, matchName)
+				return types.PriceData{}, modelPriceNotConfiguredError(matchName, info.UserId)
 			}
 		}
 	}

relay/responses_handler.go

@@ -143,7 +143,7 @@ func ResponsesHelper(c *gin.Context, info *relaycommon.RelayInfo) (newAPIError *
 		if err != nil {
 			info.OriginModelName = originModelName
 			info.PriceData = originPriceData
-			return types.NewError(err, types.ErrorCodeModelPriceError, types.ErrOptionWithSkipRetry())
+			return types.NewError(err, types.ErrorCodeModelPriceError, types.ErrOptionWithSkipRetry(), types.ErrOptionWithStatusCode(http.StatusBadRequest))
 		}
 		service.PostTextConsumeQuota(c, info, usageDto, nil)