When to invoke this skill

Detects global vs vendored install, runs the upgrade, and shows what's new. Use when asked to "upgrade gstack", "update gstack", or "get latest version".

Voice triggers (speech-to-text aliases): "upgrade the tools", "update the tools", "gee stack upgrade", "g stack upgrade".

/gstack-upgrade

Upgrade gstack to the latest version and show what's new.

Inline upgrade flow

This section is referenced by all skill preambles when they detect UPGRADE_AVAILABLE.