artifact-patch-git-apply-smoke expects a worktree prefix Git does not emit

[chubes4]

Problem

The unchanged artifact-patch-git-apply-smoke fails on main because it expects the patch header to retain the fixture's workspace/plugin/ prefix, while git diff --binary --no-ext-diff --src-prefix=a/ --dst-prefix=b/ runs with the fixture root as its working tree and emits a repository-relative path.

Observed failure:

AssertionError: The input did not match /^diff --git a\/workspace\/plugin\/added\.txt b\/workspace\/plugin\/added\.txt/m

Actual:
diff --git a/added.txt b/added.txt

Command:

npm run smoke -- --group=artifact

Expected

The smoke fixture should assert the repository-relative patch contract Git actually produces, or construct a parent repository when the workspace/plugin/ prefix is load-bearing. The assertion should be deterministic across supported Git versions.

Notes

This was found while testing #2023. The accessibility/focus oracle diff does not touch scripts/artifact-patch-git-apply-smoke.ts or its patch implementation.