hermes update had two interactive [Y/n] prompts with no bypass:
1. Config migration (after new env/config options are added)
2. Autostash restore (when uncommitted work was stashed before pull)
hermes uninstall already has --yes/-y; mirrors that.
Under --yes:
- Config-migrate prompt → auto-yes, migrate_config(interactive=False)
so new config fields are applied but API-key prompts are skipped
(user runs 'hermes config migrate' later for those). Matches
gateway-mode semantics.
- Stash-restore prompt → auto-yes, git stash apply runs automatically.
Closes the 'can I hermes update -y, No ! Fix' gap reported by @murelux.
