gen-graphql: no root operation type is emitted, so the generated document is not servable #64

GraphqlGenerator emits type definitions only. It names no root operation type, which a schema has to provide (GraphQL spec, October 2021, §3.3.1), so the generated document describes a type system but is not servable.

Reproduce on any schema:

uv run gen-graphql tests/linkml/test_generators/input/kitchen_sink.yaml

The output has no type Query, and validate_schema reports Query root type must be provided.

LinkML already carries tree_root, so the root class is known. What is not decided is the shape of the generated query fields: a single field returning a list, a field per class, identifier arguments, and whether anything is emitted at all when no class sets tree_root. That is a design decision rather than a bug fix, which is why #63 leaves it out and documents it under "Known gaps".

Downstream projects work around it by owning the whole generation pass, which also duplicates the object-type and enum emission that the generator already does correctly.