ci: harden distribution smoke workflow

[ulises-jeremias]

Summary

• harden distribution smoke checks for uvx, Docker, Homebrew, and AUR
• avoid fragile --help | head pipelines and accept semver within CLI output
• add a workflow step summary with published channel versions
• document how to manually dispatch and close distribution smoke work with a green run

Test plan

• ruby -e 'require "yaml"; YAML.load_file(ARGV[0]); puts "yaml ok"' .github/workflows/smoke-distribution.yml
• git diff --check

Closes#193