Add an official Agent Skill for Colima

### Description

colima is excellent at managing container runtimes through its CLI. as AI coding agents increasingly operate development environments, it would be useful for colima to provide an official [Agent Skill](https://agentskills.io/) based on the open Agent Skills specification.

an official skill could help agents:
- start, stop, restart, and inspect colima safely
- configure runtimes, Kubernetes, and profiles using the appropriate CLI options
- diagnose common issues using colima’s recommended commands
- distinguish normal lifecycle operations from destructive actions such as colima delete
- this would give agents a portable, discoverable, and maintainable way to use colima correctly, instead of relying on ad hoc prompts or agent-specific instructions.

would the maintainers be open to including an official skill in this repository, for example under skills/colima/SKILL.md, or recommending another official location?