get_record() JSON-parses application/jsonl and other application/json* types and raises InvalidResponseBodyError #1140

KeyValueStoreClient.get_record() JSON-parses the body whenever the content type matches ^application/json (key_value_store.py#L48-L64). That prefix also matches types whose body is not a single JSON document, such as application/jsonl and application/json-seq. A record saved with set_record('items', '{"a":1}\n{"a":2}', content_type='application/jsonl') cannot be read back with get_record(): response.json() fails and the client raises InvalidResponseBodyError. Types like application/json-patch+json happen to parse, because their body is valid JSON.

The JS client uses the same prefix to decide whether to decode the body as text, but JSON-parses only the exact type application/json (body_parser.ts#L4-L5, #L40). It returns application/jsonl and application/json-patch+json records as strings. Structured-syntax types such as application/ld+json or application/vnd.api+json match neither prefix and come back as raw bytes in both clients.

Expected behavior

get_record() returns application/jsonl, application/json-seq and other application/json* types whose body is not a single JSON document as text, so reading them back no longer fails. Parsing only the exact application/json type, as the JS client does, would also turn application/json-patch+json records from a dict into a string. That part changes return types and is best settled together with apify-client-js#1067.

✍️ Drafted by Claude Code