Codex models are chosen by family

When agents run on Codex, "Agents and models" and a card's model menu now offer model families (Sol, Astra, Terra, Luna) instead of versions, with Sol as the preset. Every Codex agent starts on the newest model of its family that Codex offers on the machine where the agent runs, so what an agent runs on no longer depends on Codex's own local configuration. A model saved before reads as its family, and a Codex too old to list its models is named as needing an update.