GHSA-vr7g-88fq-vhq3: Paperclip: OS Command Injection via Execution Workspace cleanupCommand

Paperclip AI v2026.403.0 contains a critical OS command injection vulnerability in its execution workspace lifecycle. An attacker can inject arbitrary shell commands into the `cleanupCommand` field (a parameter that specifies what to clean up after a workspace closes) via the `PATCH /api/execution-workspaces/:id` endpoint, and these commands are executed without any validation when the workspace is archived. In the default `local_trusted` deployment mode, this attack requires no authentication and works on Linux, macOS, and Windows systems with Git installed.