feat(analytics): 修改默认时间范围为 24 小时

frontend/src/pages/Analytics.tsx

@@ -84,7 +84,7 @@ const getAnalyticsBreakdownCacheKey = (range: AnalyticsRange, dimension: Analyti
 const getInitialAnalyticsRange = (): AnalyticsRange => {
   const cachedRange = readScopedCache<AnalyticsRange>(ANALYTICS_RANGE_CACHE_KEY)?.data;
 
-  return RANGE_OPTIONS.some((option) => option.value === cachedRange) ? cachedRange : "7d";
+  return (cachedRange && RANGE_OPTIONS.some((option) => option.value === cachedRange)) ? cachedRange : "24h";
 };
 
 export function Analytics() {
@@ -229,7 +229,7 @@ export function Analytics() {
   return (
     <PageContainer
       title="总览看板"
-      description="聚合查看请求、成本、成功率与关键维度分布。详细排查请进入使用日志页面。"
+      description="聚合查看请求、成本、成功率与关键维度分布。"
       actions={
         <div className="flex items-center gap-2">
           <div className="w-28">

frontend/src/pages/SystemSettings.tsx

@@ -328,7 +328,7 @@ export function SystemSettings() {
                   <Bot className="h-4 w-4" />
                   发送测试消息
                 </div>
-                <p className="text-sm text-muted-foreground">
+                <p className="text-xs text-muted-foreground/60">
                   {!telegramConfigComplete
                     ? "请先填写完整的 Bot Token 和 Chat ID。"
                     : telegramSecurityVerified

src/analytics/query.ts

@@ -270,8 +270,8 @@ const getRangeConfig = (range?: string): { range: AnalyticsRange; config: RangeC
     }
 
     return {
-        range: "7d",
-        config: RANGE_CONFIG["7d"],
+        range: "24h",
+        config: RANGE_CONFIG["24h"],
     };
 };