docs(changeset): the metadata-core line states what the fixture pin asserts, not a whole-object parse

Claude-Session: https://claude.ai/code/session_017qmjVjz61scwQFLfspdBX6
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

.changeset/23809-select-option-kind.md

@@ -29,6 +29,6 @@ The Studio object designer's options repeater offers `kind`; the field form's op
 The other packages follow the new key:
 
 - **`@objectstack/platform-objects`.** The metadata-form translation bundles (`./metadata-translations`) carry the options repeater's new `kind` row, with its label and help text in zh-CN, ja-JP and es-ES.
-- **`@objectstack/metadata-core`.** The published contract fixture `FLS_CONTRACT_OBJECT` (`@objectstack/metadata-core/testing`) names `salary_grade` as its `stageField`, so its two options now declare `kind: 'open'` and the fixture still parses through `ObjectSchema`.
+- **`@objectstack/metadata-core`.** The published contract fixture `FLS_CONTRACT_OBJECT` (`@objectstack/metadata-core/testing`) names `salary_grade` as its `stageField`, so its two options now declare `kind: 'open'`, and the fixture meets the stage-field rule: `ObjectSchema` raises no issue at `stageField` or under `fields.salary_grade.options`. The fixture is not otherwise a spec-valid object (its `script` actions carry no `body` or `target`), and this change leaves that as it was.
 
 <!-- adr-0087: registered stage-field-option-kind-required -->