The API should have an endpoint to list label settings.

### Description
The API should provide an endpoint that allows users to retrieve a list of label settings. This endpoint would return the label configurations and settings, including their attributes, in a structured format.

### Rationale
1. **Centralized Management**: Exposing label settings via an API endpoint allows developers to retrieve and manage label configurations in a programmatic way.
2. **Consistency**: Ensures that the label settings can be accessed uniformly across applications, avoiding discrepancies in label usage or setup.
3. **Automation**: This feature will facilitate automated configuration and auditing of label settings, especially useful in CI/CD pipelines and integrations.
4. **Ease of Integration**: Providing label settings through an API endpoint will simplify the process for third-party tools or internal dashboards to display and manage labels.

### Expected Behavior
1. A new endpoint, such as `/label-settings`, returns a list of label settings in JSON format.
2. The response should include:
- Label name
- Color
- Description
- Default state (if applicable)
- Categories or groups (if applicable)

### API Example
```http
GET /label-settings
```

### Sample Response

```json
{
"labels": [
{
"name": "bug",
"color": "#d73a4a",
"description": "Indicates a bug or issue",
"default": true
},
{
"name": "enhancement",
"color": "#a2eeef",
"description": "New feature or request",
"default": false
}
]
}
```

### Additional Notes
- The endpoint should support pagination for large sets of labels.
- Consider including filters (e.g., by default state or category) to retrieve specific label configurations.
- Support for versioning in case label settings evolve over time would be beneficial.