agenthub update: fetch + reset install to origin/<branch> + reinstall + rebuild, so users never touch git or pnpm. Robust to a dirty working tree (the 'commit before pull' wall) by resetting to remote; guards unpushed local commits and refuses to discard them. Adds a daily, non-blocking update hint on startup (detached background fetch + instant local comparison, like gh/npm/brew) that never auto-applies. Tests for the non-git-install path.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
