List saved knowledge document versions

Reads retained saved snapshots of a non-archived knowledge document. Partner tokens require knowledge-docs; API keys or delegate tokens use knowledge read access. Delegate callers must remain active company members and currently be able to view the document; membership, document and team authorization use primary reads. API keys and partner tokens are company-scoped. Archived, deleted, or inaccessible documents return 404. There is no archived override. Snapshots older than the current document creation time are excluded so a reused document ID cannot expose a deleted document history. These are saved versions, not unsaved drafts or a complete edit audit: rapid saves may merge and older history may be pruned (normally 50 versions retained). savedBy records the saver, not necessarily the author of every passage; Hiro before/after snapshots both name the approver. No restore or mutation is performed. Versions sort by savedAt descending, then version ID descending. Date bounds are inclusive instants; date-only values mean midnight UTC without end-of-day expansion. A filtered list may omit a predecessor needed for a comparison: omit the date filter to retrieve earlier versions. Metadata only; use the version detail endpoint for text.