Previously `isPureJjRepo` returned true whenever the resolved jj and git roots merely differed. That punishes the legitimate inverse-nesting case: a real git checkout (vendored repo, fixture, independent nested checkout) living UNDER an outer pure jj workspace. Both `jj.repo.root` and `git.repo.root` walk upward from cwd and return the closest ancestor — so the deeper root is the one the user is actually working inside, and Git automation against the inner checkout never touches the surrounding jj tree.
`isPureJjRepo` now returns true iff jj is the *deeper* ancestor (or no git is present at all). The new `isStrictDescendant` helper does the depth check via `path.relative`. Added unit + integration tests covering both nesting directions on all three surfaces (`utils/jj`, `task/worktree`, `autoresearch/git`).
Refs #1935
roboomp
b6aafab3c1