bug: codex model variants are out of order

[NathanFlurry]

Summary

Codex model variants are returned in a non-logical order.

Repro

curl -sS localhost:2468/v1/agents/codex/models | jq

Current response includes variants like:

• gpt-5.2-codex: ["high", "low", "medium", "xhigh"]
• gpt-5.2: ["high", "low", "medium", "xhigh"]
• gpt-5.1-codex-max: ["high", "low", "medium", "xhigh"]

Expected

Variants should be returned in a stable logical order (ascending reasoning effort), e.g.:

• low, medium, high, xhigh

For models that only support a subset, preserve that same ordering of the subset.

Why this matters

The UI currently reflects backend ordering, so the selector appears inconsistent and confusing.