A failed `git stash pop --index` can restore unrelated untracked files before
exiting on a tracked conflict while still preserving the stash entry. The
previous fallback only reset tracked/index state, leaving those untracked files
in the working tree for subsequent task baselines.
Record the top stash entry's untracked paths before popping and clean exactly
those paths if the pop fails after preflight. Add a regression that forces the
fallback branch and verifies the worktree returns clean with the stash preserved.
Fixes#4175
roboomp
abd0e2bdcc