Add proto-generated Dart files for the gRPC delivery service:
- delivery_service.pb.dart: Proto message types for routes, deliveries,
addresses, orders, contacts, and command request/response messages
- delivery_service.pbgrpc.dart: gRPC client and service base classes
with methods for queries (GetDeliveryRoutes, GetDeliveries) and
commands (CompleteDelivery, MarkDeliveryUncompleted, SkipDelivery,
UploadDeliveryPicture)
Co-Authored-By: Claude <noreply@anthropic.com>
