Prefer v2 websockets if available (#12428)

And also cleanup settings flow to avoid reading many separate flags.

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Co-authored-by: Codex <noreply@openai.com>

codex-rs/core/tests/suite/client.rs

@@ -4,6 +4,7 @@ use codex_core::ModelProviderInfo;
 use codex_core::NewThread;
 use codex_core::Prompt;
 use codex_core::ResponseEvent;
+use codex_core::ResponsesWebsocketVersion;
 use codex_core::ThreadManager;
 use codex_core::WireApi;
 use codex_core::auth::AuthCredentialsStoreMode;
@@ -1353,8 +1354,7 @@ async fn azure_responses_request_includes_store_and_reasoning_ids() {
         provider.clone(),
         SessionSource::Exec,
         config.model_verbosity,
-        false,
-        false,
+        None::<ResponsesWebsocketVersion>,
         false,
         false,
         None,