[BETA] MVP for Payroll Hub API for Partners.

Use this endpoint to fetch sync records for a sync request you received via
webhook.

1. Use the syncRequestId from the webhook payload.
2. The response shape depends on which webhook triggered the sync (identifier
   may be employeeId only; employeeId + effectiveDate for changes; or
   employeeId + effectiveDate + timeOffRequestId for time off).
3. Each record's data object uses vendor field names from your Payroll
   Connect integration template as keys.
4. Complete the sync (fetch all pages) before the webhook's expiringAt.
5. The response includes templateId and templateName.

Pagination: Use limit (1–200) and responseMetadata.nextCursor until
nextCursor is null.

Rate limit: 5 requests per minute per auth.

OAuth scope (app-user): payrollhub.employee_sync:write