## Why
The TUI has no voice picker, and realtime start requests omit the voice preference. Voice selection also needs to reflect the active project's effective server settings, which can differ from cached local settings.
## What changed
- Add `/voice settings` with the server's voice catalog and current effective selection, falling back to the built-in catalog when unavailable.
- Save `realtime.voice` through the app server and reread effective settings before confirming the selection. Report save failures and overrides.
- Resolve the effective voice for each realtime start. Apply selections to the next voice conversation without interrupting live audio, and retain compatibility with servers that lack `config/read` or return unknown voice names.
## Testing
Add picker and confirmation snapshots, plus request tests covering persistence, server defaults, catalog fallback, unknown voices, config read failures, overrides, and project settings after thread switches.
GitOrigin-RevId: d47e3da6c1164053c5be9d1da0f5932f2a09261f
Benjamin Carlsson
9c9451131f