What problem does it solve? Keeping gstack up to date is tedious when installs vary between global git clones, local git checkouts, and vendored copies, and manual upgrades risk losing local changes or leaving stale vendored copies behind. ## Core Features & Use Cases - Install Type Detection: Automatically detects whether gstack is installed as a global git repo, local git repo, or vendored copy, and applies the correct upgrade path. - Safe Upgrade with Rollback: Stashes local changes, backs up vendored installs, and restores from backup if the setup step fails. - Vendored Copy Sync: Detects and updates a secondary local vendored copy so global and project-level installs stay in sync. - Update Preferences: Supports auto-upgrade mode, snoozing reminders with escalating backoff, and disabling update checks entirely. - Use Case: A developer sees an UPGRADE_AVAILABLE notice while running another gstack skill; this skill asks for confirmation, upgrades the install, syncs the vendored copy, and summarizes what changed in the new version. ## Quick Start Ask the assistant to upgrade gstack to the latest version and show what is new.