The Git-bundled GPG on Windows (C:\Program Files\Git\usr\bin\gpg.exe) is
an MSYS2-based binary that uses POSIX path conventions internally. When
Windows-style paths with backslashes and drive letters (D:\a\_temp\...)
are passed as arguments, GPG may fail to resolve them correctly, resulting
in a fatal error (exit code 2).
Fix: add a toGpgPath() helper that converts Windows paths to MSYS2 POSIX
format (/d/a/_temp/...) before passing them to any gpg command. On Linux
and macOS the helper is a no-op.
Applied to all four paths used in verifyPackageSignature:
- gpgHome (--homedir argument)
- publicKeyFile (--import argument)
- signaturePath (--verify signature argument)
- archivePath (--verify data argument)