Utilize jj (Jujutsu) for local version control instead of Git. Activate this skill when a repository contains a `.jj/` directory, the user or project configuration specifies jj, the user explicitly requests 'use jj', or any version control operation is required within a jj-managed repository. Also, use this skill when the user requests commit, branch, stash, rebase, or any Git-like operation in a jj repository. If the repository type is uncertain, verify the existence of a `.jj/` directory.