WorkRequestSerializer workspace name collision

While testing the documentation with an alternate scope, I noticed that most commands were happily accepted on the default workspace, even when not targetting the default scope.

It appears the WorkRequestSerializer doesn't filter by scope and hence is subject to name collision:

class WorkRequestSerializer(serializers.ModelSerializer[WorkRequest]):
...
    workspace = serializers.SlugRelatedField(
        queryset=Workspace.objects.all(), slug_field="name"
    )

There may be other similar issues to check when deserializing debusine CLI requests on the server.

Report time in #395 (closed).