Claude Code plugin registration

[bennypowers]

Important

Agents working on this issue must read all comments and take them into account, and act according to consensus from discussions in the issue thread.

User story

As a Claude Code user working with RHDS, I want to install RHDS skills with a single command, so that all skills and MCP tools are available immediately.

Register and test the Claude Code plugin.

Goals

• Claude Code users can install RHDS skills with a single command and immediately use them
• All skills and agents load correctly and are invocable
• Bundled MCP config registers cem and asimonim servers automatically

Non-goals

• Cursor-specific testing (see Submit to Cursor marketplace #21)

Implementation notes

Steps:

1. Validate all .claude-plugin/ manifests (marketplace.json + per-plugin plugin.json)
2. Test installation: claude plugin add RedHat-UX/red-hat-design-skills
3. Verify each skill is listed and invocable
4. Verify bundled MCP config registers cem and asimonim tools
5. Document installation in README

Prerequisites: Milestones 1-3 minimum (scaffold + HTML/CSS plugin content).