Bring back /buddy as a permanent (opt-in) feature

The /buddy easter egg shipped for April 1st (changelog entry: "hatch a small creature that watches you code") was genuinely fun and gave the CLI a bit of personality. Now that we're past April it's gone.

Request: bring it back as a permanent opt-in feature. Suggestions:

• Off by default so it doesn't surprise anyone in serious contexts.
• Toggle via /buddy to summon and /buddy off to dismiss, or a setting in ~/.claude/settings.json.
• Optional: let the creature react to events (long-running tool calls, errors, successful builds) so it earns its keep beyond just sitting there.

Small thing, but the kind of personality detail that makes the tool feel less like a faceless agent. Would happily take it as a hidden flag rather than a default.