Adds a new Phase 4 section to the cli-builder skill that teaches how
to wrap a CLI tool in an agentskills.io-compliant SKILL.md wrapper,
creating the two-layer architecture: CLI as execution engine + skill
as trigger surface. Includes a complete worked example (weather-cli)
with frontmatter conventions, essential commands, gotchas, and auth
wiring documentation.
Signed-off-by: Jasper <magnus@groktop.us>
