Status: IN
A version is visible to a transaction only if its creator committed, was not in the reader's `active_at_start` set, and has a lower `tx_id` — all three must hold
Source: entries/2026/05/29/topic-mvcc-snapshot-isolation.md
created_visible = (
created_by == tx.tx_id or # own writes
(created_by in self._committed and # committed
created_by not in tx.active_at_start and # not in-flight at snapshot
created_by < tx.tx_id)) # started before us