✨ feat: Add completion commands

[irichu]

🚀 Description

• ✨ feat: Add completion commands
• ✅ Tested on Linux

[Copilot]

Pull request overview

This PR adds two new commands to the dotfiles management tool for handling zsh shell completions. The completion command generates completions for the dots command itself, while the completions command generates completions for various installed development tools (bat, fnm, gum, jj, mise, rustup/cargo, uv, and zellij).

Changes:

• Added completion command to output the dots command completion definition
• Added completions command to automatically generate zsh completions for multiple installed tools
• Created new script to generate completions for third-party tools

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
config/zsh/completions/_dots	Added completion entries for the new completion and completions commands
assets/scripts/main.sh	Implemented generate_completion() and generate_package_completions() functions and their command handlers
assets/scripts/completions/generate-zsh-completions.sh	New script to generate zsh completions for bat, fnm, gum, jj, mise, rustup, cargo, uv, and zellij
assets/scripts/completions/compdef_dots.zsh	Added completion entries for the new completion and completions commands (mirrors _dots file)

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[Copilot]

@irichu I've opened a new pull request, #12, to work on those changes. Once the pull request is ready, I'll request review from you.