🐛 Fix Python version check and setuptools validation on Windows

[truekasun]

fixes #1982

• python3 command is not available on Windows. Modified the checkPython function to check both python and python3 commands before returning the result

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[!NOTE] Detects Python 3 using either python or python3 and runs the setuptools check against that executable; adds .DS_Store to .gitignore.

• Doctor checks (lib/commands/doctor/checks/python-setuptools.js):
  • Detect Python 3 from either python3 or python, ensuring major version >= 3, and return the chosen executable.
  • Run setuptools import check using the detected python executable.
  • Preserve task titles and conditional setuptools requirement for Python >= 3.12.
• Repo:
  • Add .DS_Store to .gitignore.

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