Updated the README with explicit installation options for the Alive UI skill, covering global symlink, project-local copy, and CLI-based approaches. These additions provide clearer paths for users to integrate the skill into their workflows depending on their project requirements.

We've added a new 'Alive UI' skill that provides a robust product UI system, featuring interactive choice rounds and a new /alive command to drive engagement. This system includes a comprehensive design kit covering page transitions, motion, shell structures, and accessibility, alongside a custom design guard to maintain quality. This makes it significantly easier to build highly interactive, brand-aligned interfaces.