## Why
reapplies https://github.com/openai/codex/pull/22386 which was
previously reverted
Also, introduce `remoteControl/enable` and `remoteControl/disable`
app-server APIs to toggle on/off remote control at runtime for a given
running app-server instance.
## What Changed
- Adds experimental v2 RPCs:
- `remoteControl/enable`
- `remoteControl/disable`
- Adds `RemoteControlRequestProcessor` and routes the new RPCs through
it instead of `ConfigRequestProcessor`.
- Adds named `RemoteControlHandle::enable`, `disable`, and `status`
methods.
- Makes `remoteControl/enable` return an error when sqlite state DB is
unavailable, while keeping enrollment/websocket failures as async status
updates.
- Adds `AppServerRuntimeOptions.remote_control_enabled` and hidden
`--remote-control` flags for `codex app-server` and `codex-app-server`.
- Updates managed daemon startup to use `codex app-server
--remote-control --listen unix://`.
- Marks `Feature::RemoteControl` as removed and ignores
`[features].remote_control`.
- Updates app-server README entries for the new remote-control methods.
Owen Lin