[FEATURE] add language configuration for companion (Snick/Buddy)

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Feature Request

### Description
Allow users to configure the language of the companion (Snick/Buddy) that appears in the input box. Currently, the companion only speaks in English with no way to change it.

### Use Case
Non-English-speaking users (e.g., Brazilian Portuguese speakers) would benefit from having the companion communicate in their preferred language. This would make the experience more natural and inclusive for
international users.

Proposed Solution

### Proposed Solution
Add a companion.language (or similar) setting in settings.json that accepts a locale code (e.g., "pt-BR", "es", "fr"), allowing the companion to respond in the configured language.

### Example
```json
{
"companion": {
"language": "pt-BR"
}
}

Alternative Solutions

_No response_

Priority

Low - Nice to have

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_