Feature request: Allow customizing the companion (Nuzzlock) name

Summary

The companion character (Nuzzlock) that appears beside the input box is a nice touch, but currently the name is hardcoded and not configurable. It would be great to allow users to customize the companion's name via settings.

Proposed solution

Add a companion.name field in settings.json or .claude/settings.local.json:

{
  "companion": {
    "name": "Fardeen"
  }
}

This would update the system prompt reference and speech bubble attribution to use the custom name.

Why

• Personalization makes the tool feel more like your own
• Teams could name it after their mascot or a team member
• Simple config change with minimal implementation effort

Current behavior

The companion is always called "Nuzzlock" with no way to change it. The name is injected via the system prompt at runtime and doesn't appear in any user-editable config.