Method withCache

src/utils/Cursor.ts:1462–1469

(key: string, compute: () => T)

  }

  private withCache<T>(key: string, compute: () => T): T {
    const cached = this.navigationCache.get(key)
    if (cached !== undefined) return cached as T

    const result = compute()
    this.navigationCache.set(key, result as number)
    return result
  }

  nextOffset(offset: number): number {
    return this.withCache(`next:${offset}`, () => {