chore(zsh): add standard modelines to remaining libraries

[ss-o]

Summary

• add the canonical Emacs and Vim Zsh modelines immediately after the shebang in the three remaining library files
• keep the change comment-only with no runtime behavior changes
• preserve the reviewed signed commit discovered during archive-first workspace cleanup

Verification

• git diff --check passes
• all eight tracked .zsh files pass zsh -n
• the existing rpm2cpio.zsh redirection diagnostic is identical on next and this branch

Closes #354

[Copilot]

Pull request overview

This PR standardizes editor metadata in the Zi Zsh libraries by adding the canonical Emacs and Vim modelines immediately after the shebang in the remaining library files that lacked them, keeping the changes comment-only.

Changes:

• Add the canonical Emacs Zsh mode line after the shebang in three library files.
• Add the canonical Vim modeline after the Emacs mode line in those files.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
lib/zsh/single-line.zsh	Adds canonical Emacs/Vim Zsh modelines after the existing shebang.
lib/zsh/rpm2cpio.zsh	Adds canonical Emacs/Vim Zsh modelines after the existing shebang.
lib/zsh/git-process-output.zsh	Adds canonical Emacs/Vim Zsh modelines after the existing shebang.