- Wipe commands/gsd/ and get-shit-done/ before copying
- Delete only gsd-*.md agents (preserves user agents)
- Add confirmation step to /gsd:update with changelog preview
- Warn users about clean install behavior before updating
Adds SessionStart hook that checks npm in background, caches result.
Statusline shows "⬆ /gsd:update │" when update available.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>