Function findHighestTaskId

src/utils/tasks.ts:272–278

* Finds the highest task ID ever assigned, considering both existing files * and the high water mark (for deleted/reset tasks).

(taskListId: string)

 * and the high water mark (for deleted/reset tasks).
 */
async function findHighestTaskId(taskListId: string): Promise<number> {
  const [fromFiles, fromMark] = await Promise.all([
    findHighestTaskIdFromFiles(taskListId),
    readHighWaterMark(taskListId),
  ])
  return Math.max(fromFiles, fromMark)
}

/**
 * Creates a new task with a unique ID.