Feature request: Companion (Cobble/buddy) language configuration

Description

Currently there is no way to configure the language/locale of the Cobble companion (/buddy) feature. Users working in non-English environments (e.g., Portuguese pt-BR) would benefit from being able to set the companion's display language.

Proposed Solution

Add a companion.locale or companion.language setting in ~/.claude/settings.json:

{
  "companion": {
    "locale": "pt-BR"
  }
}

Or alternatively, have the companion respect the existing system locale or a global locale setting.

Use Case

Users who configure Claude Code to respond in their native language (via CLAUDE.md instructions) still see the companion messages in English, creating an inconsistent experience.

Environment

• Claude Code on Windows 11
• User language: Portuguese (pt-BR)