Fix poetry installation on macOS when Python from Xcode Command Line Tools

[caorantaoyao]

Root cause: On macOS, when Python 3.x is installed by the Xcode Command Line Tools, the base interpreter is a stub (e.g. /usr/bin/python3 -> /Library/Developer/CommandLineTools/usr/bin/python3). Creating a virtual environment with the stdlib venv module from this stub produces a venv whose bin/python carries an unresolvable @executable_path/../Python3 loader reference. As a result, pip (and therefore the poetry install) fails with a dyld error: Library not loaded: @executable_path/../Python3.

Fix: When sys.platform == "darwin" and the interpreter path points into /Library/Developer/CommandLineTools, force the installer to use the existing virtualenv zipapp bootstrap path (--always-copy), which creates a self-contained virtual environment that is not affected by the broken stdlib venv layout.

Behavior: The new branch only triggers on macOS for the Command Line Tools stub interpreter. On all other platforms and Python installations the existing venv code path is unchanged.

[vercel]

@caorantaoyao is attempting to deploy a commit to the Poetry Team on Vercel.

A member of the Team first needs to authorize it.

[caorantaoyao]

Duplicate of #187. Closing in favor of the updated PR.