feat: game lobby service

user/internal/ports/errors.go

@@ -22,10 +22,10 @@ var (
 )
 
 var (
-	// ErrRaceNameConflict reports that a mutation specifically failed because a
-	// race-name lookup or canonical reservation is already owned by another
-	// user. The sentinel still matches ErrConflict via errors.Is so callers can
+	// ErrUserNameConflict reports that a mutation specifically failed because
+	// the auto-generated `user_name` lookup is already owned by another user.
+	// The sentinel still matches ErrConflict via errors.Is so callers can
 	// preserve the stable public conflict semantics while collecting more
 	// precise observability.
-	ErrRaceNameConflict = fmt.Errorf("%w: race name conflict", ErrConflict)
+	ErrUserNameConflict = fmt.Errorf("%w: user name conflict", ErrConflict)
 )