The previous fix set git config --global before clone, but on systems
where atomic writes are broken (OneDrive, antivirus, NTFS filter
drivers), even writing ~/.gitconfig fails with 'Invalid argument'.
Fix: inject the config via GIT_CONFIG_COUNT/KEY/VALUE environment
variables, which git reads before performing any file I/O. This
bypasses the chicken-and-egg problem where git can't write the config
file that would fix its file-writing issue.
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