New tables: custom_field_definition, custom_field_value Supports field types: text, number, date, dropdown, checkbox Endpoints: - GET/POST /repos/{owner}/{repo}/custom-fields - GET/PATCH/DELETE /repos/{owner}/{repo}/custom-fields/{fieldId} - GET /repos/{owner}/{repo}/issues/{index}/custom-fields - PUT /repos/{owner}/{repo}/issues/{index}/custom-fields/{fieldId} - DELETE /repos/{owner}/{repo}/issues/{index}/custom-fields/{fieldId} Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>