fix: expose account_stats_cost in usage log API and fix frontend display

Backend:
- Add AccountStatsCost field to AdminUsageLog DTO
- Map AccountStatsCost in UsageLogFromServiceAdmin mapper
- Replace println with slog.Warn in api_key_auth_cache_impl.go

Frontend:
- Add account_stats_cost to AdminUsageLog TypeScript interface
- Usage tooltip and table: prefer account_stats_cost when available,
  fallback to total_cost * multiplier (mirrors SQL COALESCE logic)
- Excel export: same COALESCE fallback

backend/cmd/server/VERSION

@@ -1 +1 @@
-0.1.110.24
+0.1.110.25

backend/internal/handler/dto/mappers.go

@@ -628,6 +628,7 @@ func UsageLogFromServiceAdmin(l *service.UsageLog) *AdminUsageLog {
 		ModelMappingChain:     l.ModelMappingChain,
 		BillingTier:           l.BillingTier,
 		AccountRateMultiplier: l.AccountRateMultiplier,
+		AccountStatsCost:      l.AccountStatsCost,
 		IPAddress:             l.IPAddress,
 		Account:               AccountSummaryFromService(l.Account),
 	}

backend/internal/handler/dto/types.go

@@ -427,6 +427,8 @@ type AdminUsageLog struct {
 
 	// AccountRateMultiplier 账号计费倍率快照（nil 表示按 1.0 处理）
 	AccountRateMultiplier *float64 `json:"account_rate_multiplier"`
+	// AccountStatsCost 自定义定价规则计算的账号统计费用（nil 表示使用默认公式）
+	AccountStatsCost *float64 `json:"account_stats_cost,omitempty"`
 
 	// IPAddress 用户请求 IP（仅管理员可见）
 	IPAddress *string `json:"ip_address,omitempty"`

backend/internal/service/api_key_auth_cache_impl.go

@@ -6,6 +6,7 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"log/slog"
 	"math/rand/v2"
 	"time"
 
@@ -99,7 +100,7 @@ func (s *APIKeyService) StartAuthCacheInvalidationSubscriber(ctx context.Context
 		s.authCacheL1.Del(cacheKey)
 	}); err != nil {
 		// Log but don't fail - L1 cache will still work, just without cross-instance invalidation
-		println("[Service] Warning: failed to start auth cache invalidation subscriber:", err.Error())
+		slog.Warn("failed to start auth cache invalidation subscriber", "error", err)
 	}
 }
 

frontend/src/components/admin/usage/UsageTable.vue

@@ -155,7 +155,7 @@
               </div>
             </div>
             <div v-if="row.account_rate_multiplier != null" class="mt-0.5 text-[11px] text-gray-400">
-              A ${{ (row.total_cost * row.account_rate_multiplier).toFixed(6) }}
+              A ${{ (row.account_stats_cost != null ? row.account_stats_cost * (row.account_rate_multiplier ?? 1) : row.total_cost * row.account_rate_multiplier).toFixed(6) }}
             </div>
           </div>
         </template>
@@ -328,7 +328,7 @@
           <div class="flex items-center justify-between gap-6 border-t border-gray-700 pt-1.5">
             <span class="text-gray-400">{{ t('usage.accountBilled') }}</span>
             <span class="font-semibold text-green-400">
-              ${{ (((tooltipData?.total_cost || 0) * (tooltipData?.account_rate_multiplier ?? 1)) || 0).toFixed(6) }}
+              ${{ (tooltipData?.account_stats_cost != null ? (tooltipData.account_stats_cost * (tooltipData?.account_rate_multiplier ?? 1)) : ((tooltipData?.total_cost || 0) * (tooltipData?.account_rate_multiplier ?? 1))).toFixed(6) }}
             </span>
           </div>
         </div>

frontend/src/types/index.ts

@@ -1057,6 +1057,8 @@ export interface AdminUsageLog extends UsageLog {
 
   // 账号计费倍率（仅管理员可见）
   account_rate_multiplier?: number | null
+  // 自定义定价规则计算的账号统计费用（nil 时使用 total_cost * multiplier）
+  account_stats_cost?: number | null
 
   // 用户请求 IP（仅管理员可见）
   ip_address?: string | null

frontend/src/views/admin/UsageView.vue

@@ -495,7 +495,7 @@ const exportToExcel = async () => {
         log.cache_read_cost?.toFixed(6) || '0.000000', log.cache_creation_cost?.toFixed(6) || '0.000000',
         log.rate_multiplier?.toPrecision(4) || '1.00', (log.account_rate_multiplier ?? 1).toPrecision(4),
         log.total_cost?.toFixed(6) || '0.000000', log.actual_cost?.toFixed(6) || '0.000000',
-        (log.total_cost * (log.account_rate_multiplier ?? 1)).toFixed(6), log.first_token_ms ?? '', log.duration_ms,
+        ((log.account_stats_cost ?? log.total_cost) * (log.account_rate_multiplier ?? 1)).toFixed(6), log.first_token_ms ?? '', log.duration_ms,
         log.request_id || '', log.user_agent || '', log.ip_address || ''
       ])
       if (rows.length) {