This service exposes a GraphQL API for managing and querying vehicles.
Users can register vehicles and fetch vehicles associated only with their own account.

The service provides the following queries and mutations:

Returns a list of vehicles belonging exclusively to the authenticated user's account.

• If searchPlate is provided, returns vehicles matching the plate filter.
• If no filter is provided, returns all vehicles for the user's account.

Returns a single vehicle by its unique ID.

• The vehicle returned is scoped to the authenticated user's account.
• If no vehicle matches the given ID or it does not belong to the user, the result is null.

Registers a new vehicle under the authenticated user's account.

• Requires the user to be authenticated.
• Accepts registrationNumber and accountId (UUID) as inputs.
• Returns the newly registered vehicle as a GraphQL object.