Fixes #13012

GitHub Actions now supports uploading artifacts with archive: false, but the CLI always attempts to unzip artifacts regardless of their format. This causes a "not a valid zip file" error when downloading non-zipped artifacts.

Root Cause
The downloadArtifact function in http.go always treats downloaded artifacts as zip files and attempts to extract them without checking the Content-Type header.

Fix

• Check Content-Type header to detect if artifact is a zip file
• If Content-Type is not application/zip or application/x-zip-compressed, write the file directly to destination without attempting to unzip
• Pass artifact name through the download pipeline to ensure correct filename for non-zipped artifacts

Changes

• Modified platform interface to accept artifact name parameter
• Updated downloadArtifact to check Content-Type and handle non-zipped artifacts
• Updated test to match new signature

Testing

• Existing test updated to match new interface signature
• Manual testing with non-zipped artifacts would verify the fix