## Why
Saved model selections can outlive their bundled catalog entries and still need migration guidance.
## What changed
- Remove `gpt-5.2` and `gpt-5.4-mini` from the bundled model catalog.
- Preserve migration from saved `gpt-5.4-mini` selections to `gpt-5.6-luna` when the old model is absent, while respecting catalog-provided migration metadata.
- Update tests and snapshots to use current models or explicit test fixtures, and remove the obsolete prompt fixture.
## Testing
Extend migration tests to cover catalog metadata precedence, saved selections, replacement model and reasoning-effort persistence, acknowledged prompts, and missing or hidden migration targets.
GitOrigin-RevId: 82beea504cc4a15699677c28a61ec0939af3069c
## What changed
- Add `approvalsReviewer` to the experimental `turn/settings/update` API.
- Apply reviewer changes to subsequently captured steps and new background approval requests while preserving pending approvals and future-thread defaults.
- Allow reviewer-only updates without `step_model_switching`, while continuing to enforce managed reviewer restrictions and model-required auto review.
- Use an explicit live reviewer update for MCP approvals while retaining refreshed thread defaults for clients that have not set one.
## Testing
- Cover switching between user and automatic review during a live turn, future-turn isolation, and managed-authority rejection.
GitOrigin-RevId: e1216b09c6a7972c2c9eaf4955d8d57d60604ca1
## What changed
- Add the experimental `turn/settings/update` method for changing `model`,
`effort`, `summary`, and `serviceTier` on a specific live turn without
changing future turns.
- Report whether the update was applied or the target turn was unavailable,
and reject unsupported fields, disabled feature use, unsafe model changes,
and direct updates to parent-owned subagents.
- Document the method's feature requirements, null handling, and limits.
## Testing
- Cover current-turn and future-turn isolation, rejected and unavailable
targets, feature and capability gates, saved threads, and subagent ownership.
GitOrigin-RevId: 18440f6d7ee5fcd06ae23bd41b22c492b62bb2b5