⚡ Bolt: [성능 개선] SessionTimelineChart 데이터 매핑 방식 O(N+M)으로 최적화

[seonghobae]

💡 What: SessionTimelineChart의 차트 데이터를 렌더링하기 위해 usageTimeline의 각 버킷에 toolCalls를 매핑하는 과정에서 사용되던 $O(N \times M)$ 복잡도의 중첩 .filter() 루프를 제거하고 두 포인터 기반의 $O(N+M)$ 방식으로 최적화했습니다.
🎯 Why: 시계열 데이터 매핑에 중첩 필터를 사용하면 도구 호출이나 이벤트 수가 많아질수록 렌더링을 차단하거나 지연시키는 병목 현상이 발생합니다. 이벤트 배열이 이미 시계열이라는 점을 활용하면 선형 시간 내에 동일한 데이터를 훨씬 빠르게 처리할 수 있습니다.
📊 Impact: 이벤트 수가 많은 세션 조회 시 렌더링 관련 오버헤드가 현저히 감소하며, 특히 배열 순회에 의한 GC 작업이 줄어들어 전반적인 프론트엔드 반응성이 개선됩니다.
🔬 Measurement: pnpm --filter @argos/web run test src/components/dashboard/session-timeline-chart.test.tsx 를 실행하여 해당 차트 컴포넌트의 기능 무결성을 확인했으며, Typecheck 와 Lint 통과도 확인했습니다.

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PR created automatically by Jules for task 3965610122832810651 started by @seonghobae

[google-labs-jules]

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[seonghobae]

Closing as superseded, with lineage preserved here. PR #271 merged the forward-cursor cumulative tool aggregation into protected developmental (merge commit 4f8796ec8c3a8d130136029650705714724cb0ac); current protected head dfe476798bb85bb24aea6674b84124d9098ebf78 retains the stronger implementation, input-immutability behavior, stable first-seen ordering, and focused regression tests. This PR remains based on 9ef092b9979d46b96063701e706521d21407d6a9 and carries no unique product delta that is not already covered by protected main. The current-base timestamp-allocation follow-up is tracked separately in #425.

[google-labs-jules]

Closing as superseded, with lineage preserved here. PR #271 merged the forward-cursor cumulative tool aggregation into protected developmental (merge commit 4f8796ec8c3a8d130136029650705714724cb0ac); current protected head dfe476798bb85bb24aea6674b84124d9098ebf78 retains the stronger implementation, input-immutability behavior, stable first-seen ordering, and focused regression tests. This PR remains based on 9ef092b9979d46b96063701e706521d21407d6a9 and carries no unique product delta that is not already covered by protected main. The current-base timestamp-allocation follow-up is tracked separately in #425.

Understood. Acknowledging that this work is now obsolete and stopping work on this task.