import { useMemo } from "react";import { deriveThreadCheckpointSummaries } from "@t3tools/client-runtime/state/thread-checkpoints";import type { OrchestrationV2ThreadProjection } from "@t3tools/contracts";import { inferCheckpointTurnCountByRunId } from "../session-logic";import type { TurnDiffSummary } from "../types"; export function useTurnDiffSummaries(projection: OrchestrationV2ThreadProjection | null) {  const turnDiffSummaries = useMemo<ReadonlyArray<TurnDiffSummary>>(() => {    if (projection === null) {      return [];    }    return deriveThreadCheckpointSummaries(projection);  }, [projection]);   const inferredCheckpointTurnCountByRunId = useMemo(    () => inferCheckpointTurnCountByRunId(turnDiffSummaries),    [turnDiffSummaries],  );   return { turnDiffSummaries, inferredCheckpointTurnCountByRunId };}