Prompt for launcher selection in vendor:publish

[techmahedy]

Summary

vendor:publish previously had two explicit modes (--launcher=, --tag=) and one silent default: run it with no options and it published assets from every registered launcher at once. There was no way to pick a single launcher without knowing its exact class name up front.

This adds an interactive picker for that default case, using the choice() prompt.

1. Running vendor:publish with no --launcher/--tag now lists every registered launcher that actually has publishable paths, plus an All option, and asks which to publish.
2. Non-interactive environments (CI, scripts, --no-interaction) are unaffected — falls back to publishing everything, same as before. Added a small isInteractive() wrapper on Command for this.
3. If no launcher has anything publishable, it says so instead of silently reporting Published assets from 0 launchers.