@startuml uc-01-register
autonumber
title UC-01 Register Account (design sequence)
actor Guest
participant "AuthBoundary\n«POST /api/auth/register»" as boundary <<boundary>>
participant "AccountRegistry\nsb-api::routes::register" as control <<control>>
participant "UserAccount\nsb-shared::user::User" as entity <<entity>>

== Register ==
Guest -> boundary : name (3-32), password (>= 6)
boundary -> control : register(name, password)
alt name invalid / password too short
  control --> boundary : 400
else name taken
  control --> boundary : 409 CONFLICT
else valid
  control -> entity : hash password (argon2, sb-auth)
  control -> entity : assign player role + next id
  control -> entity : persist (sb-db)
  control --> boundary : JWT HS256 (player role)
  boundary --> Guest : {token, user_id, name, role}
end
@enduml