## What changed
- Parse `codex_rollout_budget_units` from completed Responses API usage into
`TokenUsage`.
- Keep the provider-only value out of serialized protocol, JSON schema, and
TypeScript representations.
## Testing
- Cover the value in unit and end-to-end SSE response parsing tests.
GitOrigin-RevId: a53d4202beb9c8985d25894cb10e7c01f20b2a44