@actions/exec seems to ignore working-directory workflow setting

Describe the bug
In an action configured with a working-directory setting, the default CWD of exec.exec() seems to ignore that setting.

To Reproduce
Create a workflow like this:

name: "Docker: Build & Test"

on: [push] # irrelevant
jobs:
  build:
    name: Build Docker image
    runs-on: ubuntu-latest
    defaults:
      run:
        working-directory: mydir # this bit
    steps:
      - uses: some/action

in a repository with some files in mydir at the root

And an action containing this:

import * as exec from '@actions/exec'
async function run(): Promise<void> {
  await exec.exec('pwd')
  await exec.exec('ls')
}
run()

Expected behavior
The pwd output should reflect the working-directory setting. The ls output should show the contents of that directory.

Additional context
Both the workflow-level and job-level working-directory setting are ignored. It's not clear how to get at that value to set it manually, if it's even possible.

Start with the provided workflow and the TypeScript calls to @actions/exec.exec('pwd') and exec('ls'), then inspect how the execution context is established. Confirm whether workflow- and job-level working-directory values are available to an action, and document or implement behavior that matches the expected directory output if the toolkit can access them.