Auto-obfuscation cannot stage skip-worktree note path

[c0da-ricon]

Problem

With shiv:notes 0.8.19, committing a staged readable note can fail during pre-commit auto-obfuscation when the mapped obfuscated path is marked skip-worktree by the deobfuscated checkout.

Observed sequence:

1. Modify notes/Status.md in an unlocked/deobfuscated home.

2. Run notes stage notes/Status.md.

3. Run git commit.

4. The pre-commit hook reports Auto-obfuscating 1 file(s)..., writes the mapped obfuscated file, then git add fails with:

   The following paths and/or pathspecs matched paths that exist
   outside of your sparse-checkout definition, so will not be
   updated in the index:
   notes/1474d5a8
   

The repository was not using sparse checkout (git sparse-checkout list reported that this worktree is not sparse), but git ls-files -v showed the obfuscated path with the S skip-worktree flag.

The failed hook left an interrupted state:

AD notes/Status.md

notes status then correctly warned that Status.md was double-tracked as both readable and obfuscated.

Recovery used

git rm --cached --ignore-unmatch notes/Status.md
git update-index --no-skip-worktree notes/1474d5a8
git add notes/1474d5a8
git commit

The note content was preserved, and the repository was subsequently merged and pushed cleanly.

Expected

Auto-obfuscation should stage its mapped obfuscated path even when that path was intentionally marked skip-worktree by deobfuscation. Possible fixes include clearing the flag before staging or using the appropriate sparse-aware git add path. A failed hook should ideally restore or clearly guide recovery from the readable-path staging state.