Shell completion (bash/zsh)

[trmxvibs]

Add tab-completion for pkgwrap/pkw commands and package names in
bash/zsh. argparse has some built-in completion support, or a static
completion script can be hand-written. Would make CLI usage noticeably
smoother for daily users.

[jollsdmello804]

Hi @trmxvibs,

I'd like to work on this issue if it's available.

I'm planning to add shell completion support for both Bash and Zsh, keeping it consistent with the current CLI and installation process. I'll also update the documentation with installation and usage instructions if needed.

Could you please assign this issue to me? Thanks!