CVE-2026-35454: Code Extension Marketplace has a Zip Slip Path Traversal

The Code Extension Marketplace is an open-source alternative to the VS Code Marketplace. Prior to 2.4.2, Zip Slip vulnerability in coder/code-marketplace allowed a malicious VSIX file to write arbitrary files outside the extension directory. ExtractZip passed raw zip entry names to a callback that wrote files via filepath.Join with no boundary check; filepath.Join resolved .. components but did not prevent the result from escaping the base path. This vulnerability is fixed in 2.4.2.