captureRepoDeltaPatch records the delta against `HEAD + WIP`, so the
patch's context lines and blob SHAs reference the WIP-modified files.
commitPatchToBranchWorktree then tried to apply that patch to a fresh
worktree pinned at HEAD, which failed hard whenever the WIP-side file
was missing from HEAD's index (untracked WIP files, staged-new WIP
files) or when --3way could not resolve an overlap.
commitPatchToBranchWorktree now tries plain apply first, then `--3way`
(which cleanly subtracts WIP via the shared ODB blob for tracked files),
and only when both fail replays baseline WIP into the temp worktree so
the delta's context lines up, rewinding WIP-only files afterward so
they never leak into the branch commit.
Added git.ls.tree helper for the WIP-only-file filter and a set of
regression tests covering the untracked, staged-new, and overlap
scenarios.
Fixes#4136
roboomp
286e971bfe