auth: move domain mode below app wire types (#29721)

## Why

Authentication mode is a domain concept used by login, model selection,
telemetry, and transports. Keeping the canonical type in app-server
protocol forces those lower-level crates to depend on an unrelated wire
API.

## What changed

- Added canonical `codex_protocol::auth::AuthMode` domain values.
- Kept the app-server wire DTO unchanged and added an explicit app-side
conversion.
- Removed production app-server-protocol dependencies from login,
model-provider-info, models-manager, and otel call paths.

## Stack

This is PR 2 of 6, stacked on [PR
#29714](https://github.com/openai/codex/pull/29714). Review only the
delta from `codex/split-json-rpc-protocols`. Next: [PR
#29722](https://github.com/openai/codex/pull/29722).

## Validation

- Auth and login coverage passed in the focused protocol/domain test
run.
- App-server account and auth conversion coverage passed.

codex-rs/app-server-transport/src/transport/remote_control/tests.rs

@@ -18,7 +18,6 @@ use crate::transport::CHANNEL_CAPACITY;
 use crate::transport::ConnectionOrigin;
 use crate::transport::TransportEvent;
 use base64::Engine;
-use codex_app_server_protocol::AuthMode;
 use codex_app_server_protocol::ConfigWarningNotification;
 use codex_app_server_protocol::JSONRPCMessage;
 use codex_app_server_protocol::RemoteControlConnectionStatus;
@@ -36,6 +35,7 @@ use codex_login::CodexAuth;
 use codex_login::save_auth;
 use codex_login::token_data::TokenData;
 use codex_login::token_data::parse_chatgpt_jwt_claims;
+use codex_protocol::auth::AuthMode;
 use codex_state::RemoteControlEnrollmentRecord;
 use codex_state::StateRuntime;
 use futures::SinkExt;

codex-rs/app-server-transport/src/transport/remote_control/websocket.rs

@@ -1813,7 +1813,6 @@ mod tests {
     use crate::transport::remote_control::protocol::StreamId;
     use crate::transport::remote_control::protocol::normalize_remote_control_url;
     use chrono::Utc;
-    use codex_app_server_protocol::AuthMode;
     use codex_app_server_protocol::ConfigWarningNotification;
     use codex_app_server_protocol::JSONRPCMessage;
     use codex_app_server_protocol::JSONRPCNotification;
@@ -1826,6 +1825,7 @@ mod tests {
     use codex_login::save_auth;
     use codex_login::token_data::TokenData;
     use codex_login::token_data::parse_chatgpt_jwt_claims;
+    use codex_protocol::auth::AuthMode;
     use codex_state::StateRuntime;
     use futures::StreamExt;
     use pretty_assertions::assert_eq;