GHSA-4vp2-6q8c-pvq2: @anthropic-ai/claude-code has an Insecure Temporary File in /copy Command that Enables Response Disclosure and Symlink-Based File Write

Claude Code's `/copy` command had a serious security flaw where it saved responses to an easily guessable file location (`/tmp/claude/response.md`) that any user on the system could read, potentially exposing secrets or credentials. An attacker could also create a symlink (a shortcut to another file) at that location to trick the command into overwriting any file they chose. This vulnerability required the attacker and a privileged user to be on the same computer.