feat: 实现基于滑动窗口的实时RPM/TPM统计

- 添加系统级分钟统计，支持1-60分钟可配置时间窗口
- 新增 getRealtimeSystemMetrics 方法计算滑动窗口内的平均值
- 前端显示实时RPM/TPM，标注时间窗口和数据来源
- 修复 EditApiKeyModal 中模型限制和客户端限制复选框状态错误
- 优化性能：使用Pipeline批量操作替代Promise.all
- TPM包含所有token类型：input、output、cache_creation、cache_read
- 添加降级方案：实时数据不可用时返回历史平均值

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

web/admin-spa/src/stores/dashboard.js

@@ -26,6 +26,10 @@ export const useDashboardStore = defineStore('dashboard', () => {
     todayCacheReadTokens: 0,
     systemRPM: 0,
     systemTPM: 0,
+    realtimeRPM: 0,
+    realtimeTPM: 0,
+    metricsWindow: 5,
+    isHistoricalMetrics: false,
     systemStatus: '正常',
     uptime: 0,
     systemTimezone: 8 // 默认 UTC+8
@@ -129,6 +133,7 @@ export const useDashboardStore = defineStore('dashboard', () => {
         const overview = dashboardResponse.data.overview || {}
         const recentActivity = dashboardResponse.data.recentActivity || {}
         const systemAverages = dashboardResponse.data.systemAverages || {}
+        const realtimeMetrics = dashboardResponse.data.realtimeMetrics || {}
         const systemHealth = dashboardResponse.data.systemHealth || {}
         
         dashboardData.value = {
@@ -151,6 +156,10 @@ export const useDashboardStore = defineStore('dashboard', () => {
           todayCacheReadTokens: recentActivity.cacheReadTokensToday || 0,
           systemRPM: systemAverages.rpm || 0,
           systemTPM: systemAverages.tpm || 0,
+          realtimeRPM: realtimeMetrics.rpm || 0,
+          realtimeTPM: realtimeMetrics.tpm || 0,
+          metricsWindow: realtimeMetrics.windowMinutes || 5,
+          isHistoricalMetrics: realtimeMetrics.isHistorical || false,
           systemStatus: systemHealth.redisConnected ? '正常' : '异常',
           uptime: systemHealth.uptime || 0,
           systemTimezone: dashboardResponse.data.systemTimezone || 8