fix(frontend): auto-fetch report data when campaignId changes

useCampaignReport hook 缺少 useEffect 自动触发数据获取，导致打开报告抽屉时
显示空白。添加 useEffect 监听 campaignId 变化，自动调用 refetch。

- 新增 useEffect 在 campaignId 变化时自动获取数据

frontend/web/src/hooks/useCampaignReport.ts

@@ -1,4 +1,4 @@
-import { useState, useCallback, type Dispatch, type SetStateAction } from 'react'
+import { useState, useCallback, useEffect, type Dispatch, type SetStateAction } from 'react'
 import { campaignsApi, runsApi, type CampaignReport, type Run, type CampaignTimelineEntry, type CampaignAnalysis, type CampaignComparison } from '../api'
 
 interface CampaignReportData {
@@ -59,6 +59,12 @@ export function useCampaignReport(campaignId: string | null): UseCampaignReportR
     }
   }, [campaignId])
 
+  useEffect(() => {
+    if (campaignId) {
+      void refetch(false)
+    }
+  }, [campaignId, refetch])
+
   const setAnalysis: Dispatch<SetStateAction<CampaignAnalysis | null>> = (value) => {
     setData((prev) => ({
       ...prev,