feat: game lobby service

gateway/README.md

@@ -486,8 +486,11 @@ in v1 is exactly:
 - `lobby.application.submitted`
 - `lobby.membership.approved`
 - `lobby.membership.rejected`
+- `lobby.membership.blocked`
 - `lobby.invite.created`
 - `lobby.invite.redeemed`
+- `lobby.race_name.registration_eligible`
+- `lobby.race_name.registered`
 
 `lobby.application.submitted` is published toward `Gateway` only for the
 private-game owner flow. The public-game variant is email-only.