Editor schema for kusaw.yaml

Put this comment on the first line of a kusaw.yaml. Editors that speak the YAML language server then check the file against a schema on disk:

# yaml-language-server: $schema=./.kusaw/factory.schema.json

kusaw validate writes that file into the factory's data directory. That is the data_dir value, or .kusaw next to kusaw.yaml when the key is absent or the file did not parse. kusaw schema prints the same document.

The schema $id, https://factory.local/schema/factory.v2.schema.json, is only a name. Kusaw does not fetch it, and editors should not either.