KGClient.query() ignores id_key parameter when validating instance_id

[apdavison]

KGClient.query() accepts an id_key parameter (default "@id") to specify which key identifies the ID in the response JSON-LD documents. This parameter is correctly used in the release_status="any" code path (line 319):

instances[instance[id_key]] = instance

However, _check_response() always hardcodes "@id" when validating the instance_id (line 202):

if str(expected_instance_id) not in response.data[0]["@id"]:
    raise Exception("mismatched instance_id")

This means that when a query uses a custom responseVocab that maps @id to a different key (e.g. "id"), calling query() with both instance_id and id_key="id" raises a KeyError: '@id' instead of using the provided id_key.

To reproduce

from fairgraph.client import KGClient

client = KGClient(host="core.kg.ebrains.eu")

# A query whose responseVocab maps @id to "id"
query = {
    "@context": {
        "@vocab": "https://core.kg.ebrains.eu/vocab/query/",
        "query": "https://schema.hbp.eu/myQuery/",
        "propertyName": {"@id": "propertyName", "@type": "@id"},
        "path": {"@id": "path", "@type": "@id"},
    },
    "meta": {
        "type": "https://openminds.om-i.org/types/DatasetVersion",
        "responseVocab": "https://schema.hbp.eu/myQuery/",
    },
    "structure": [
        {"propertyName": "query:id", "path": "@id"},
        {"propertyName": "query:fullName", "path": "https://openminds.om-i.org/props/fullName"},
    ],
}

# Raises KeyError: '@id'
result = client.query(
    query=query,
    instance_id="07554ebd-95a2-46f0-8065-d961d56ce098",
    id_key="id",
    release_status="released",
)

Expected behaviour

_check_response() should use the id_key parameter passed to query() instead of hardcoding "@id".

Suggested fix

Thread id_key through to _check_response and use it on line 202:

if str(expected_instance_id) not in response.data[0][id_key]:

Version: 0.13.2