The install skill now works like the install prompt says it should. Check first. If LDM OS is installed, show what you have and what's new. Fetch release notes for every component with an update and summarize what actually changed in 2-3 bullets. The user sees WHAT changed, not just that a version number moved. If not installed, then explain.

This is SKILL.md, the source file. wip-release deploys it to wip.computer/install/wip-ldm-os.txt automatically. No more editing the website file directly.

Partial #202.
