`maxVisible` is not working for `task.group` inside another task

[vladshcherbin]

Bug description

Root task.group with maxVisible works correctly. When used inside another task, maxVisible is ignored:

Screen.Recording.2026-06-27.at.18.14.35.mov

Reproduction

import { setTimeout } from 'node:timers/promises'
import task from 'tasuku'

await task('Root task', async () => {
  await task.group(
    (t) => Array.from({ length: 10 }, (_, i) => (
      t(`Task ${i + 1}`, () => setTimeout(500 + Math.random() * 1200))
    )),
    {
      concurrency: 1,
      maxVisible: 4
    }
  )
})

Environment

• tasuku version: 3.0.0-beta.5
• Operating System: macOS 15.7.7
• Node version: 26.1.0
• Package manager (npm/yarn/pnpm) and version: pnpm 11.8.0