goreleaser: bundle shell completions in release archives

[michael-webster]

Summary

• Adds goreleaser before hooks to generate bash and zsh completion scripts at release time
• Bundles them in release archives at the standard UNIX paths (share/bash-completion/completions/chunk, share/zsh/site-functions/_chunk)
• The Homebrew formula installs these to the standard completion directories automatically — no subprocess spawned on shell startup
• Adds --output/-o flag to chunk completion bash and chunk completion zsh so the hooks don't need shell redirection or mkdir -p wrappers (mirrors circleci-cli)
• Adds share/ to .gitignore (generated artifact)
• completion install is unchanged and continues to work as a fallback for manual curl installs

Motivation

chunk completion install was writing source <(chunk completion zsh) to .zshrc, which spawns a chunk subprocess on every new shell session. This was generating ~400 telemetry events per day from shell startups rather than intentional user invocations.

For Homebrew users (the majority), completions now land in the right system directories during installation with no runtime cost. The completion install fallback is preserved for users who install via curl.

Reproduction steps

# 1. Build the binary and verify --output creates the file and any missing parent directories
task build
./dist/chunk completion bash --output /tmp/chunk-completion-test/chunk
./dist/chunk completion zsh --output /tmp/chunk-completion-test/_chunk
head -3 /tmp/chunk-completion-test/chunk   # → bash completion header
head -3 /tmp/chunk-completion-test/_chunk  # → #compdef chunk

# 2. Run goreleaser hooks and verify share/ is populated
goreleaser build --snapshot --clean
ls -la share/bash-completion/completions/chunk share/zsh/site-functions/_chunk

# 3. Verify the files land in the release archive
goreleaser release --snapshot --clean --skip=publish,announce,validate
tar tzf dist/chunk-cli_Darwin_arm64.tar.gz | grep share
# share/bash-completion/completions/chunk
# share/zsh/site-functions/_chunk

Test plan

• Steps above pass locally
• CI passes
• After next Homebrew release: brew install chunk-cli && chunk <TAB> completes without spawning a subprocess

🤖 Generated with Claude Code