Argos JavaScript: CI Branch Name OS Command Injection in @argos-ci/core

Argos JavaScript provides official Argos SDKs for JavaScript. Prior to Argos core package version 6.2.1, attacker-controlled CI branch or ref values from GITHUB_HEAD_REF or ARGOS_BRANCH can flow through config.branch and getMergeBaseCommitSha() when hasRemoteContentAccess is false. The gitFetch() and gitMergeBase() functions in packages/core/src/ci-environment/git.ts interpolate these values into execSync() command strings executed by /bin/sh -c, so shell metacharacters in a pull-request branch name can execute arbitrary commands with the Argos upload process privileges on the CI runner. Successful exploitation can expose CI secrets, alter build artifacts, or compromise the runner. This issue is fixed in Argos core package version 6.2.1.