fix(group): harden peak-rate config handling and label peak windows with server timezone

Follow-up fixes to #3569 based on code audit:

- Expose server_timezone / server_utc_offset in public settings (and the
  __APP_CONFIG__ injection payload) and label every peak-window display
  with the server UTC offset, so users don't misread the billing window
  as browser-local time
- Unify CreateGroup/UpdateGroup peak-config sanitization via a single
  NormalizePeakRateConfig chokepoint: non-subscription groups always get
  peak fields cleared; unparseable window strings and negative
  multipliers are scrubbed when peak is disabled
- Replace hot-path time.Parse in PeakMultiplierAt with a manual HH:MM
  parser (accept set verified byte-for-byte identical to
  time.Parse("15:04") by exhaustive fuzzing) and reuse it in validation
- Revert the zero-behavior CalculateCost indirection churn in
  billing_service/gateway_service introduced by #3569
- Remove dead GetGroupPlatformMap and the duplicate deref helper in the
  admin handler package
- Share frontend peak formatting via utils/peak-rate.ts, unify the ×N
  label format, and move hardcoded Chinese tooltips to i18n keys

backend/internal/handler/admin/group_handler.go

@@ -71,13 +71,6 @@ func (f optionalLimitField) ToServiceInput() *float64 {
 	return &zero
 }
 
-func derefFloat64Default(p *float64, def float64) float64 {
-	if p != nil {
-		return *p
-	}
-	return def
-}
-
 // NewGroupHandler creates a new admin group handler
 func NewGroupHandler(adminService service.AdminService, dashboardService *service.DashboardService, groupCapacityService *service.GroupCapacityService) *GroupHandler {
 	return &GroupHandler{
@@ -292,7 +285,7 @@ func (h *GroupHandler) Create(c *gin.Context) {
 		return
 	}
 
-	if err := service.ValidatePeakRateConfig(req.SubscriptionType, req.PeakRateEnabled, req.PeakStart, req.PeakEnd, derefFloat64Default(req.PeakRateMultiplier, 1.0)); err != nil {
+	if err := service.ValidatePeakRateConfig(req.SubscriptionType, req.PeakRateEnabled, req.PeakStart, req.PeakEnd, float64ValueOrDefault(req.PeakRateMultiplier, 1.0)); err != nil {
 		response.BadRequest(c, err.Error())
 		return
 	}

backend/internal/handler/dto/settings.go

@@ -321,10 +321,14 @@ type PublicSettings struct {
 	BackendModeEnabled               bool                     `json:"backend_mode_enabled"`
 	PaymentEnabled                   bool                     `json:"payment_enabled"`
 	Version                          string                   `json:"version"`
-	BalanceLowNotifyEnabled          bool                     `json:"balance_low_notify_enabled"`
-	AccountQuotaNotifyEnabled        bool                     `json:"account_quota_notify_enabled"`
-	BalanceLowNotifyThreshold        float64                  `json:"balance_low_notify_threshold"`
-	BalanceLowNotifyRechargeURL      string                   `json:"balance_low_notify_recharge_url"`
+	// 服务器全局时区（IANA 名称与当前 UTC 偏移，如 "Asia/Shanghai" / "+08:00"）。
+	// 高峰时段等按服务器本地时间判定的窗口，前端展示时据此标注，避免用户按浏览器本地时间误读。
+	ServerTimezone              string  `json:"server_timezone"`
+	ServerUTCOffset             string  `json:"server_utc_offset"`
+	BalanceLowNotifyEnabled     bool    `json:"balance_low_notify_enabled"`
+	AccountQuotaNotifyEnabled   bool    `json:"account_quota_notify_enabled"`
+	BalanceLowNotifyThreshold   float64 `json:"balance_low_notify_threshold"`
+	BalanceLowNotifyRechargeURL string  `json:"balance_low_notify_recharge_url"`
 
 	ChannelMonitorEnabled                bool `json:"channel_monitor_enabled"`
 	ChannelMonitorDefaultIntervalSeconds int  `json:"channel_monitor_default_interval_seconds"`

backend/internal/handler/setting_handler.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/Wei-Shaw/sub2api/internal/handler/dto"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/response"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/timezone"
 	"github.com/Wei-Shaw/sub2api/internal/service"
 
 	"github.com/gin-gonic/gin"
@@ -85,6 +86,8 @@ func (h *SettingHandler) GetPublicSettings(c *gin.Context) {
 		BackendModeEnabled:               settings.BackendModeEnabled,
 		PaymentEnabled:                   settings.PaymentEnabled,
 		Version:                          h.version,
+		ServerTimezone:                   timezone.Name(),
+		ServerUTCOffset:                  timezone.UTCOffset(),
 		BalanceLowNotifyEnabled:          settings.BalanceLowNotifyEnabled,
 		AccountQuotaNotifyEnabled:        settings.AccountQuotaNotifyEnabled,
 		BalanceLowNotifyThreshold:        settings.BalanceLowNotifyThreshold,

backend/internal/pkg/timezone/timezone.go

@@ -81,6 +81,11 @@ func Name() string {
 	return tzName
 }
 
+// UTCOffset returns the current UTC offset of the configured timezone, e.g. "+08:00".
+func UTCOffset() string {
+	return getUTCOffset(Location())
+}
+
 // StartOfDay returns the start of the given day (00:00:00) in the configured timezone.
 func StartOfDay(t time.Time) time.Time {
 	loc := Location()

backend/internal/service/admin_service.go

@@ -1850,7 +1850,9 @@ func (s *adminServiceImpl) CreateGroup(ctx context.Context, input *CreateGroupIn
 	if input.PeakRateMultiplier != nil {
 		peakRateMultiplier = *input.PeakRateMultiplier
 	}
-	if err := ValidatePeakRateConfig(subscriptionType, input.PeakRateEnabled, input.PeakStart, input.PeakEnd, peakRateMultiplier); err != nil {
+	// 先归一化（非订阅分组清空高峰配置、清洗停用状态下的脏字段）再校验，与 UpdateGroup 同一收口。
+	peakRateEnabled, peakStart, peakEnd, peakRateMultiplier := NormalizePeakRateConfig(subscriptionType, input.PeakRateEnabled, input.PeakStart, input.PeakEnd, peakRateMultiplier)
+	if err := ValidatePeakRateConfig(subscriptionType, peakRateEnabled, peakStart, peakEnd, peakRateMultiplier); err != nil {
 		return nil, err
 	}
 
@@ -1923,9 +1925,9 @@ func (s *adminServiceImpl) CreateGroup(ctx context.Context, input *CreateGroupIn
 		AllowImageGeneration:            input.AllowImageGeneration,
 		ImageRateIndependent:            input.ImageRateIndependent,
 		ImageRateMultiplier:             imageRateMultiplier,
-		PeakRateEnabled:                 input.PeakRateEnabled,
-		PeakStart:                       input.PeakStart,
-		PeakEnd:                         input.PeakEnd,
+		PeakRateEnabled:                 peakRateEnabled,
+		PeakStart:                       peakStart,
+		PeakEnd:                         peakEnd,
 		PeakRateMultiplier:              peakRateMultiplier,
 		ImagePrice1K:                    imagePrice1K,
 		ImagePrice2K:                    imagePrice2K,
@@ -2128,14 +2130,10 @@ func (s *adminServiceImpl) UpdateGroup(ctx context.Context, id int64, input *Upd
 	if input.PeakRateMultiplier != nil {
 		group.PeakRateMultiplier = *input.PeakRateMultiplier
 	}
-	if group.SubscriptionType != SubscriptionTypeSubscription {
-		group.PeakRateEnabled = false
-		group.PeakStart = ""
-		group.PeakEnd = ""
-		group.PeakRateMultiplier = 1.0
-	}
-	// 收敛校验：Update 可能只传部分 peak 字段，需对合并后的最终配置统一校验，
-	// 防止单独修改 start/end 导致最终 start>=end 等非法配置入库。
+	// 先归一化（非订阅分组——含本次更新转为非订阅——静默清空高峰配置，清洗停用状态下的脏字段），
+	// 再收敛校验：Update 可能只传部分 peak 字段，需对合并后的最终配置统一校验，
+	// 防止单独修改 start/end 导致最终 start>=end 等非法配置入库。与 CreateGroup 同一收口。
+	group.PeakRateEnabled, group.PeakStart, group.PeakEnd, group.PeakRateMultiplier = NormalizePeakRateConfig(group.SubscriptionType, group.PeakRateEnabled, group.PeakStart, group.PeakEnd, group.PeakRateMultiplier)
 	if err := ValidatePeakRateConfig(group.SubscriptionType, group.PeakRateEnabled, group.PeakStart, group.PeakEnd, group.PeakRateMultiplier); err != nil {
 		return nil, err
 	}

backend/internal/service/billing_service.go

@@ -1080,19 +1080,15 @@ func (s *BillingService) CalculateCostWithConfig(model string, tokens UsageToken
 // 拆分为：范围内 (200k, 0) + 范围外 (10k, 10k)
 // 范围内正常计费，范围外 × 2 计费
 func (s *BillingService) CalculateCostWithLongContext(model string, tokens UsageTokens, rateMultiplier float64, threshold int, extraMultiplier float64) (*CostBreakdown, error) {
-	return s.calculateCostWithLongContext(model, tokens, rateMultiplier, threshold, extraMultiplier)
-}
-
-func (s *BillingService) calculateCostWithLongContext(model string, tokens UsageTokens, rateMultiplier float64, threshold int, extraMultiplier float64) (*CostBreakdown, error) {
 	// 未启用长上下文计费，直接走正常计费
 	if threshold <= 0 || extraMultiplier <= 1 {
-		return s.calculateCostInternal(model, tokens, rateMultiplier, "", nil)
+		return s.CalculateCost(model, tokens, rateMultiplier)
 	}
 
 	// 计算总输入 token（缓存读取 + 新输入）
 	total := tokens.CacheReadTokens + tokens.InputTokens
 	if total <= threshold {
-		return s.calculateCostInternal(model, tokens, rateMultiplier, "", nil)
+		return s.CalculateCost(model, tokens, rateMultiplier)
 	}
 
 	// 拆分成范围内和范围外
@@ -1123,7 +1119,7 @@ func (s *BillingService) calculateCostWithLongContext(model string, tokens Usage
 		CacheCreation1hTokens: tokens.CacheCreation1hTokens,
 		ImageOutputTokens:     tokens.ImageOutputTokens,
 	}
-	inRangeCost, err := s.calculateCostInternal(model, inRangeTokens, rateMultiplier, "", nil)
+	inRangeCost, err := s.CalculateCost(model, inRangeTokens, rateMultiplier)
 	if err != nil {
 		return nil, err
 	}
@@ -1133,7 +1129,7 @@ func (s *BillingService) calculateCostWithLongContext(model string, tokens Usage
 		InputTokens:     outRangeInputTokens,
 		CacheReadTokens: outRangeCacheTokens,
 	}
-	outRangeCost, err := s.calculateCostInternal(model, outRangeTokens, rateMultiplier*extraMultiplier, "", nil)
+	outRangeCost, err := s.CalculateCost(model, outRangeTokens, rateMultiplier*extraMultiplier)
 	if err != nil {
 		return inRangeCost, fmt.Errorf("out-range cost: %w", err)
 	}

backend/internal/service/gateway_service.go

@@ -9681,7 +9681,7 @@ func (s *GatewayService) calculateTokenCost(
 		// 长上下文双倍计费（如 Gemini 200K 阈值）
 		cost, err = s.billingService.CalculateCostWithLongContext(billingModel, tokens, multiplier, opts.LongContextThreshold, opts.LongContextMultiplier)
 	} else {
-		cost, err = s.billingService.CalculateCostWithServiceTier(billingModel, tokens, multiplier, "")
+		cost, err = s.billingService.CalculateCost(billingModel, tokens, multiplier)
 	}
 	if err != nil {
 		logger.LegacyPrintf("service.gateway", "Calculate cost failed: %v", err)

backend/internal/service/group.go

@@ -178,12 +178,32 @@ func matchModelPattern(pattern, model string) bool {
 }
 
 // parseMinutes 把 "HH:MM" 解析为当日分钟数（0..1439），格式非法返回 (0,false)。
+// 手工解析而非 time.Parse：本函数位于每请求的计费热路径（PeakMultiplierAt），
+// 避免对静态配置字符串重复走 layout 解析与 time.Time 分配。
+// 接受集与 time.Parse("15:04", s) 完全一致（存量数据按旧解析写入，不得收窄）：
+// 小时 1–2 位数字（0..23，允许不补零如 "1:30"），分钟固定 2 位数字（00..59）。
 func parseMinutes(hhmm string) (int, bool) {
-	t, err := time.Parse("15:04", hhmm)
-	if err != nil {
+	colon := strings.IndexByte(hhmm, ':')
+	if (colon != 1 && colon != 2) || len(hhmm)-colon-1 != 2 {
 		return 0, false
 	}
-	return t.Hour()*60 + t.Minute(), true
+	h := 0
+	for i := 0; i < colon; i++ {
+		d := hhmm[i] - '0'
+		if d > 9 {
+			return 0, false
+		}
+		h = h*10 + int(d)
+	}
+	m1, m2 := hhmm[colon+1]-'0', hhmm[colon+2]-'0'
+	if m1 > 9 || m2 > 9 {
+		return 0, false
+	}
+	m := int(m1)*10 + int(m2)
+	if h > 23 || m > 59 {
+		return 0, false
+	}
+	return h*60 + m, true
 }
 
 // PeakMultiplierAt 返回指定时刻 now 的高峰因子。
@@ -223,15 +243,15 @@ func ValidatePeakRateConfig(subscriptionType string, enabled bool, start, end st
 	if start == "" || end == "" {
 		return errors.New("peak_rate_enabled 为 true 时 peak_start 与 peak_end 必填")
 	}
-	st, err1 := time.Parse("15:04", start)
-	if err1 != nil {
+	st, okStart := parseMinutes(start)
+	if !okStart {
 		return fmt.Errorf("peak_start 格式应为 HH:MM，got %q", start)
 	}
-	en, err2 := time.Parse("15:04", end)
-	if err2 != nil {
+	en, okEnd := parseMinutes(end)
+	if !okEnd {
 		return fmt.Errorf("peak_end 格式应为 HH:MM，got %q", end)
 	}
-	if st.Hour()*60+st.Minute() >= en.Hour()*60+en.Minute() {
+	if st >= en {
 		return errors.New("peak_end 必须大于 peak_start（不支持跨天区间，如 22:00-02:00）")
 	}
 	if multiplier < 0 {
@@ -240,6 +260,32 @@ func ValidatePeakRateConfig(subscriptionType string, enabled bool, start, end st
 	return nil
 }
 
+// NormalizePeakRateConfig 归一化最终落库的高峰配置，CreateGroup 与 UpdateGroup 两条写路径共用（唯一收口）：
+//   - 非订阅类型分组不携带任何高峰配置，一律清空（enabled=false、窗口置空、倍率归 1.0）；
+//   - 订阅分组关闭高峰时保留已配置的合法窗口（便于临时停用后再启用），
+//     但清掉无法解析的脏字符串与负倍率，避免脏数据入库。
+//
+// 与 ValidatePeakRateConfig 的分工：enabled=true 时校验已保证各字段合法，本函数为无操作；
+// enabled=false 时校验放行，由本函数兜底清洗。调用顺序为先归一化、后校验，
+// 使"订阅转标准"这类更新能静默清空高峰配置而不是被校验拒绝。
+func NormalizePeakRateConfig(subscriptionType string, enabled bool, start, end string, multiplier float64) (bool, string, string, float64) {
+	if subscriptionType != SubscriptionTypeSubscription {
+		return false, "", "", 1.0
+	}
+	if !enabled {
+		if _, ok := parseMinutes(start); !ok {
+			start = ""
+		}
+		if _, ok := parseMinutes(end); !ok {
+			end = ""
+		}
+		if multiplier < 0 {
+			multiplier = 1.0
+		}
+	}
+	return enabled, start, end, multiplier
+}
+
 // computePeakAwareMultipliers 把"基础 token 倍率 base"（已含系统/分组/用户级倍率，但不含高峰）
 // 拆分为最终 token 倍率与图片按次倍率：图片按次倍率基于 base 现算、不受高峰影响；token 倍率在 base 上叠加高峰因子。
 // gateway_service.recordUsageCore 与 openai_gateway_service.RecordUsage 共用此函数，

backend/internal/service/payment_config_plans.go

@@ -74,16 +74,6 @@ type PlanGroupInfo struct {
 	ModelScopes        []string `json:"supported_model_scopes"`
 }
 
-// GetGroupPlatformMap returns a map of group_id → platform for the given plans.
-func (s *PaymentConfigService) GetGroupPlatformMap(ctx context.Context, plans []*dbent.SubscriptionPlan) map[int64]string {
-	info := s.GetGroupInfoMap(ctx, plans)
-	m := make(map[int64]string, len(info))
-	for id, gi := range info {
-		m[id] = gi.Platform
-	}
-	return m
-}
-
 // GetGroupInfoMap returns a map of group_id → PlanGroupInfo for the given plans.
 func (s *PaymentConfigService) GetGroupInfoMap(ctx context.Context, plans []*dbent.SubscriptionPlan) map[int64]PlanGroupInfo {
 	ids := make([]int64, 0, len(plans))

backend/internal/service/setting_service.go

@@ -21,6 +21,7 @@ import (
 	"github.com/Wei-Shaw/sub2api/internal/pkg/antigravity"
 	infraerrors "github.com/Wei-Shaw/sub2api/internal/pkg/errors"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/openai"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/timezone"
 	"github.com/imroc/req/v3"
 	"golang.org/x/sync/singleflight"
 )
@@ -1461,10 +1462,13 @@ type PublicSettingsInjectionPayload struct {
 	BackendModeEnabled               bool                     `json:"backend_mode_enabled"`
 	PaymentEnabled                   bool                     `json:"payment_enabled"`
 	Version                          string                   `json:"version"`
-	BalanceLowNotifyEnabled          bool                     `json:"balance_low_notify_enabled"`
-	AccountQuotaNotifyEnabled        bool                     `json:"account_quota_notify_enabled"`
-	BalanceLowNotifyThreshold        float64                  `json:"balance_low_notify_threshold"`
-	BalanceLowNotifyRechargeURL      string                   `json:"balance_low_notify_recharge_url"`
+	// 服务器全局时区（IANA 名称与当前 UTC 偏移），高峰时段等服务端本地时间窗口的展示标注用
+	ServerTimezone              string  `json:"server_timezone"`
+	ServerUTCOffset             string  `json:"server_utc_offset"`
+	BalanceLowNotifyEnabled     bool    `json:"balance_low_notify_enabled"`
+	AccountQuotaNotifyEnabled   bool    `json:"account_quota_notify_enabled"`
+	BalanceLowNotifyThreshold   float64 `json:"balance_low_notify_threshold"`
+	BalanceLowNotifyRechargeURL string  `json:"balance_low_notify_recharge_url"`
 
 	// Feature flags — MUST match the opt-in/opt-out registry in
 	// frontend/src/utils/featureFlags.ts. Missing a field here is the bug
@@ -1527,6 +1531,8 @@ func (s *SettingService) GetPublicSettingsForInjection(ctx context.Context) (any
 		BackendModeEnabled:               settings.BackendModeEnabled,
 		PaymentEnabled:                   settings.PaymentEnabled,
 		Version:                          s.version,
+		ServerTimezone:                   timezone.Name(),
+		ServerUTCOffset:                  timezone.UTCOffset(),
 		BalanceLowNotifyEnabled:          settings.BalanceLowNotifyEnabled,
 		AccountQuotaNotifyEnabled:        settings.AccountQuotaNotifyEnabled,
 		BalanceLowNotifyThreshold:        settings.BalanceLowNotifyThreshold,

frontend/src/components/channels/AvailableChannelsTable.vue

@@ -178,6 +178,8 @@ import SupportedModelChip from './SupportedModelChip.vue'
 import type { UserAvailableChannel, UserAvailableGroup, UserChannelPlatformSection } from '@/api/channels'
 import type { GroupPlatform, SubscriptionType } from '@/types'
 import { platformBadgeClass } from '@/utils/platformColors'
+import { useAppStore } from '@/stores/app'
+import { hasPeakRate as groupHasPeakRate, formatPeakRateWindow, serverTimezoneLabel } from '@/utils/peak-rate'
 
 const props = defineProps<{
   columns: {
@@ -211,15 +213,17 @@ function publicGroups(section: UserChannelPlatformSection): UserAvailableGroup[]
   return section.groups.filter((g) => !g.is_exclusive)
 }
 
+const appStore = useAppStore()
+
 function hasPeakRate(group: UserAvailableGroup): boolean {
-  return Boolean(group.peak_rate_enabled && group.peak_start && group.peak_end)
+  return groupHasPeakRate(group)
 }
 
 function peakRateLabel(group: UserAvailableGroup): string {
-  return `${group.peak_start}-${group.peak_end} ${group.peak_rate_multiplier}x`
+  return formatPeakRateWindow(group, serverTimezoneLabel(appStore.cachedPublicSettings?.server_utc_offset))
 }
 
 function peakRateTitle(group: UserAvailableGroup): string {
-  return `高峰倍率：${group.peak_start}-${group.peak_end} ${group.peak_rate_multiplier}x；token 计费的图片 token 同样适用，图片按次计费不受高峰影响`
+  return t('common.peakRateTooltip', { window: peakRateLabel(group) }) + t('common.peakRateImageNote')
 }
 </script>

frontend/src/components/common/GroupBadge.vue

@@ -30,6 +30,8 @@
 import { computed } from 'vue'
 import { useI18n } from 'vue-i18n'
 import type { SubscriptionType, GroupPlatform } from '@/types'
+import { useAppStore } from '@/stores/app'
+import { formatPeakRateWindow, serverTimezoneLabel } from '@/utils/peak-rate'
 import PlatformIcon from './PlatformIcon.vue'
 
 interface Props {
@@ -75,16 +77,26 @@ const hasCustomRate = computed(() => {
   )
 })
 
+const appStore = useAppStore()
+
 const hasPeakRate = computed(() => {
   return Boolean(props.showRate && props.peakRateEnabled && props.peakStart && props.peakEnd)
 })
 
 const peakRateText = computed(() => {
-  return `${props.peakStart}-${props.peakEnd} ×${props.peakRateMultiplier ?? 1}`
+  return formatPeakRateWindow(
+    {
+      peak_rate_enabled: props.peakRateEnabled,
+      peak_start: props.peakStart,
+      peak_end: props.peakEnd,
+      peak_rate_multiplier: props.peakRateMultiplier
+    },
+    serverTimezoneLabel(appStore.cachedPublicSettings?.server_utc_offset)
+  )
 })
 
 const peakRateTitle = computed(() => {
-  return `高峰倍率：${peakRateText.value}`
+  return t('common.peakRateTooltip', { window: peakRateText.value })
 })
 
 // 是否显示右侧标签

frontend/src/components/common/GroupOptionItem.vue

@@ -63,6 +63,8 @@ import { computed } from 'vue'
 import { useI18n } from 'vue-i18n'
 import GroupBadge from './GroupBadge.vue'
 import type { SubscriptionType, GroupPlatform } from '@/types'
+import { useAppStore } from '@/stores/app'
+import { formatPeakRateWindow, serverTimezoneLabel } from '@/utils/peak-rate'
 
 const { t } = useI18n()
 
@@ -99,16 +101,26 @@ const hasCustomRate = computed(() => {
   )
 })
 
+const appStore = useAppStore()
+
 const hasPeakRate = computed(() => {
   return Boolean(props.peakRateEnabled && props.peakStart && props.peakEnd)
 })
 
 const peakRateText = computed(() => {
-  return `${props.peakStart}-${props.peakEnd} ×${props.peakRateMultiplier ?? 1}`
+  return formatPeakRateWindow(
+    {
+      peak_rate_enabled: props.peakRateEnabled,
+      peak_start: props.peakStart,
+      peak_end: props.peakEnd,
+      peak_rate_multiplier: props.peakRateMultiplier
+    },
+    serverTimezoneLabel(appStore.cachedPublicSettings?.server_utc_offset)
+  )
 })
 
 const peakRateTitle = computed(() => {
-  return `高峰倍率：${peakRateText.value}`
+  return t('common.peakRateTooltip', { window: peakRateText.value })
 })
 
 // Rate pill color matches platform badge color

frontend/src/components/payment/SubscriptionPlanCard.vue

@@ -103,6 +103,8 @@ import { computed } from 'vue'
 import { useI18n } from 'vue-i18n'
 import type { SubscriptionPlan } from '@/types/payment'
 import type { UserSubscription } from '@/types'
+import { useAppStore } from '@/stores/app'
+import { hasPeakRate as groupHasPeakRate, formatPeakRateWindow, serverTimezoneLabel } from '@/utils/peak-rate'
 import {
   platformAccentBarClass,
   platformBadgeLightClass,
@@ -144,12 +146,12 @@ const rateDisplay = computed(() => {
   return `×${Number(rate.toPrecision(10))}`
 })
 
-const hasPeakRate = computed(() => {
-  return Boolean(props.plan.peak_rate_enabled && props.plan.peak_start && props.plan.peak_end)
-})
+const appStore = useAppStore()
+
+const hasPeakRate = computed(() => groupHasPeakRate(props.plan))
 
 const peakRateDisplay = computed(() => {
-  return `${props.plan.peak_start}-${props.plan.peak_end} ×${props.plan.peak_rate_multiplier ?? 1}`
+  return formatPeakRateWindow(props.plan, serverTimezoneLabel(appStore.cachedPublicSettings?.server_utc_offset))
 })
 
 const MODEL_SCOPE_LABELS: Record<string, string> = {

frontend/src/components/payment/__tests__/SubscriptionPlanCard.spec.ts

@@ -1,5 +1,6 @@
 import { mount } from "@vue/test-utils";
 import { describe, expect, it } from "vitest";
+import { createPinia } from "pinia";
 import { createI18n } from "vue-i18n";
 import SubscriptionPlanCard from "../SubscriptionPlanCard.vue";
 
@@ -42,7 +43,7 @@ const mountPlanCard = (groupPlatform: string) =>
         is_active: true,
       },
     },
-    global: { plugins: [i18n] },
+    global: { plugins: [i18n, createPinia()] },
   });
 
 describe("SubscriptionPlanCard", () => {

frontend/src/i18n/locales/en.ts

@@ -252,6 +252,8 @@ export default {
     loading: 'Loading...',
     submitting: 'Submitting...',
     justNow: 'just now',
+    peakRateTooltip: 'Peak rate: {window}',
+    peakRateImageNote: '; image tokens billed as tokens are also affected, per-image billing is unaffected',
     save: 'Save',
     saved: 'Saved successfully',
     deleted: 'Deleted successfully',

frontend/src/i18n/locales/zh.ts

@@ -252,6 +252,8 @@ export default {
     loading: '加载中...',
     submitting: '提交中...',
     justNow: '刚刚',
+    peakRateTooltip: '高峰倍率：{window}',
+    peakRateImageNote: '；token 计费的图片 token 同样适用，图片按次计费不受高峰影响',
     save: '保存',
     saved: '保存成功',
     deleted: '删除成功',

frontend/src/types/index.ts

@@ -227,6 +227,10 @@ export interface PublicSettings {
   google_oauth_enabled: boolean
   backend_mode_enabled: boolean
   version: string
+  // 服务器全局时区（IANA 名称与当前 UTC 偏移），高峰时段等服务端本地时间窗口的展示标注用；
+  // 可选：注入的 __APP_CONFIG__ 旧缓存可能缺失
+  server_timezone?: string
+  server_utc_offset?: string
   balance_low_notify_enabled: boolean
   account_quota_notify_enabled: boolean
   balance_low_notify_threshold: number

frontend/src/utils/peak-rate.ts

@@ -0,0 +1,33 @@
+/**
+ * 高峰时段倍率的共享展示逻辑。
+ *
+ * 高峰窗口由后端按服务器全局时区判定（Group.PeakMultiplierAt），
+ * 前端展示必须带上服务器时区标注（来自公共设置 server_utc_offset），
+ * 避免用户按浏览器本地时间误读计费窗口。
+ */
+
+export interface PeakRateFields {
+  peak_rate_enabled?: boolean
+  peak_start?: string
+  peak_end?: string
+  peak_rate_multiplier?: number
+}
+
+export function hasPeakRate(fields?: PeakRateFields | null): boolean {
+  return Boolean(fields?.peak_rate_enabled && fields.peak_start && fields.peak_end)
+}
+
+/** "+08:00" → "UTC+08:00"；旧缓存无该字段时返回空串，调用方降级为不带时区标注 */
+export function serverTimezoneLabel(utcOffset?: string | null): string {
+  return utcOffset ? `UTC${utcOffset}` : ''
+}
+
+/** "14:00-18:00 ×2 (UTC+08:00)"，tzLabel 为空时省略括号部分 */
+export function formatPeakRateWindow(
+  fields: PeakRateFields | null | undefined,
+  tzLabel?: string
+): string {
+  if (!hasPeakRate(fields) || !fields) return ''
+  const base = `${fields.peak_start}-${fields.peak_end} ×${fields.peak_rate_multiplier ?? 1}`
+  return tzLabel ? `${base} (${tzLabel})` : base
+}

frontend/src/views/user/PaymentView.vue

@@ -262,6 +262,7 @@ import { useAppStore } from '@/stores'
 import { paymentAPI } from '@/api/payment'
 import { extractApiErrorMessage, extractI18nErrorMessage } from '@/utils/apiError'
 import { isMobileDevice } from '@/utils/device'
+import { hasPeakRate, formatPeakRateWindow, serverTimezoneLabel, type PeakRateFields } from '@/utils/peak-rate'
 import type { SubscriptionPlan, CheckoutInfoResponse, CreateOrderResult, OrderType } from '@/types/payment'
 import AppLayout from '@/components/layout/AppLayout.vue'
 import AmountInput from '@/components/payment/AmountInput.vue'
@@ -304,14 +305,12 @@ function getDaysRemaining(expiresAt: string): number {
   return Math.max(0, Math.ceil(diff / (1000 * 60 * 60 * 24)))
 }
 
-function subscriptionHasPeakRate(sub: { group?: { peak_rate_enabled?: boolean; peak_start?: string; peak_end?: string } | null }): boolean {
-  const group = sub.group
-  return Boolean(group?.peak_rate_enabled && group.peak_start && group.peak_end)
+function subscriptionHasPeakRate(sub: { group?: PeakRateFields | null }): boolean {
+  return hasPeakRate(sub.group)
 }
 
-function subscriptionPeakRateLabel(sub: { group?: { peak_start?: string; peak_end?: string; peak_rate_multiplier?: number } | null }): string {
-  const group = sub.group
-  return `${group?.peak_start}-${group?.peak_end} ×${group?.peak_rate_multiplier ?? 1}`
+function subscriptionPeakRateLabel(sub: { group?: PeakRateFields | null }): string {
+  return formatPeakRateWindow(sub.group, serverTimezoneLabel(appStore.cachedPublicSettings?.server_utc_offset))
 }
 
 const loading = ref(true)
@@ -713,11 +712,11 @@ const planValiditySuffix = computed(() => {
 })
 
 function planHasPeakRate(plan: SubscriptionPlan): boolean {
-  return Boolean(plan.peak_rate_enabled && plan.peak_start && plan.peak_end)
+  return hasPeakRate(plan)
 }
 
 function planPeakRateLabel(plan: SubscriptionPlan): string {
-  return `${plan.peak_start}-${plan.peak_end} ×${plan.peak_rate_multiplier ?? 1}`
+  return formatPeakRateWindow(plan, serverTimezoneLabel(appStore.cachedPublicSettings?.server_utc_offset))
 }
 
 function selectPlan(plan: SubscriptionPlan) {

frontend/src/views/user/SubscriptionsView.vue

@@ -257,6 +257,7 @@ import type { UserSubscription } from '@/types'
 import AppLayout from '@/components/layout/AppLayout.vue'
 import Icon from '@/components/icons/Icon.vue'
 import { formatDateOnly } from '@/utils/format'
+import { hasPeakRate, formatPeakRateWindow, serverTimezoneLabel } from '@/utils/peak-rate'
 import { platformBorderClass, platformBadgeClass, platformButtonClass, platformLabel } from '@/utils/platformColors'
 import { getRemainingDurationParts, isOneTimeDailyQuota, type RemainingDurationParts } from '@/utils/subscriptionQuota'
 
@@ -278,13 +279,11 @@ const subscriptions = ref<UserSubscription[]>([])
 const loading = ref(true)
 
 function subscriptionHasPeakRate(subscription: UserSubscription): boolean {
-  const group = subscription.group
-  return Boolean(group?.peak_rate_enabled && group.peak_start && group.peak_end)
+  return hasPeakRate(subscription.group)
 }
 
 function subscriptionPeakRateLabel(subscription: UserSubscription): string {
-  const group = subscription.group
-  return `${group?.peak_start}-${group?.peak_end} ×${group?.peak_rate_multiplier ?? 1}`
+  return formatPeakRateWindow(subscription.group, serverTimezoneLabel(appStore.cachedPublicSettings?.server_utc_offset))
 }
 
 async function loadSubscriptions() {