Feature: Document SELinux bind-mount note for local devcontainer usage

Describe the enhancement or feature you would like

When using the CPython devcontainer image on SELinux-enabled Linux hosts, a plain bind mount may fail with Permission denied inside the container.

Example:

docker run -it --rm \
  -v "$PWD:/workspace" \
  -w /workspace \
  ghcr.io/python/devcontainer:latest

In that case, a SELinux-compatible bind mount works:

  docker run -it --rm \
  -v "$PWD:/workspace:Z" \
  -w /workspace \
  ghcr.io/python/devcontainer:latest

Without relabeling, /workspace may not be readable from inside the container.

It may be helpful to add a short note to the local Docker/devcontainer documentation for SELinux-enabled hosts, preferably using the :Z bind-mount form.

Describe alternatives you have considered

As an alternative workaround, this also works:

docker run -it --rm \
  --security-opt label=disable \
  -v "$PWD:/workspace" \
  -w /workspace \
  ghcr.io/python/devcontainer:latest

Additional context

No response

ローカルの Docker/devcontainer ドキュメントで、issue に示されている bind-mount の使用方法を調べてください。SELinux が有効な Linux ホスト向けに、:Z 形式の bind-mount を使う短い注記を追加し、適切であればラベル付けを無効にする回避策にも言及してください。ドキュメントが通常の mount で失敗する理由を説明し、動作するコマンドを示していれば完了です。