fix/#506-audience-time-based-sync 자유토론 타이머 청중 동기화 및 초기화·진영 전환 오류 수정 - #507

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache@v4, actions/checkout@v4, actions/setup-node@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Replace `shouldSkipSentryEvent(new·Error('Request·was·aborted·by·server'))).toBe(⏎······false,⏎····` with `⏎······shouldSkipSentryEvent(new·Error('Request·was·aborted·by·server')),⏎····).toBe(false`

Replace `⏎··getDisplayDataByEvent,⏎··AudienceDisplayData,⏎` with `·getDisplayDataByEvent,·AudienceDisplayData·`