feat: point AI agents at the skill from --help and init

[angeloashmore]

Resolves: N/A

Description

An agent that runs npx prismic --help or prismic init gets no pointer to the Prismic skill. It falls back to training data instead.

Add a hint to two places:

• The root --help description.
• prismic init success output, both the starter-handoff branch and the plain-init branch.

The hint names the skill install command first and the docs command second: "For AI agents: run npx skills add --global prismicio/skills to install the Prismic skill, or run npx prismic docs list for a quick reference."

No skill detection is added. The hint always shows, for simplicity.

Checklist

• If my changes require tests, I added them.
• If my changes affect backward compatibility, it has been discussed.
• If my changes require an update to the CONTRIBUTING.md guide, I updated it.

Preview

N/A

How to QA

Run npx prismic --help and check the description includes the AI-agent hint. Run prismic init against a repo and check the success output includes the same hint.