Install shell completions & man pages

Completions for bash, zsh, fish, and powershell are emitted via Cobra's built-in completion subcommand:

# Load completions for the current shell session (bash)
source <(planwerk-agent completion bash)

# Install persistently (zsh, Homebrew example)
planwerk-agent completion zsh > "$(brew --prefix)/share/zsh/site-functions/_planwerk-agent"

# Fish
planwerk-agent completion fish > ~/.config/fish/completions/planwerk-agent.fish

When installed from Homebrew, deb, or rpm packages, completions and man pages (man planwerk-agent) are installed automatically. Packages are produced by goreleaser — see .goreleaser.yml.

For local development, regenerate the artifacts into completions/ and docs/man/:

make completions
make man