Problem

The Bitrix24 REST API v3 method `rest.scope.list` is not yet supported by the SDK.

The method is present in the OpenAPI schema (`docs/open-api/openapi.json`) and returns a list of available scopes with optional filtering by module, controller, or method name.

Proposed solution

Add a service method that wraps `rest.scope.list` following the existing patterns in `src/Services/`.

Since the method belongs to the `rest` scope, the implementation should go into a new `Rest` service builder and service class under `src/Services/Rest/`.

Response structure

The method returns a nested map (not a flat list): `module → controller → method → item`.

Example call with `filterModule=rest`:

```json
{
"result": {
"rest": {
"scope": {
"list": {
"scope": "rest.scope.list",
"title": "List метод для scope",
"description": "Метод для получения всех доступных scope приложения",
"fields": null
}
}
}
},
"time": { ... }
}
```

Each leaf item has:

• `scope` — full method name (e.g. `rest.scope.list`)
• `title` — human-readable title
• `description` — description
• `fields` — `null` or field metadata

The result class must flatten the nested structure into a list of `ScopeMethodItemResult` objects.

Parameters

• `filterModule` (string, optional) — filter by module name (e.g. `rest`, `tasks`)
• `filterController` (string, optional) — filter by controller name
• `filterMethod` (string, optional) — filter by method name

Acceptance criteria

• `RestServiceBuilder` registered in `src/Services/ServiceBuilder.php`
• `Rest\Service\Scope` service class implements `rest.scope.list` with parameter mapping (`filterModule`, `filterController`, `filterMethod`)
• Result class flattens the nested `module → controller → method` response into a flat list
• Result item `@property-read` annotations cover all response fields: `scope`, `title`, `description`, `fields`
• `ApiEndpointMetadata('rest.scope.list', ...)` attribute present with `ApiVersion::v3`
• Unit test passes (`make test-unit`)
• Integration test passes, including annotation and type-cast checks
• `CHANGELOG.md` is updated with an issue link