Enable conversation-scoped speed selection for Cloud turns (#61178)

## What changed

- Stage Cloud speed choices for the next new turn in the conversation, alongside pending model and effort selections. Update the displayed conversation speed after admission without changing the local default.
- Offer speed commands supported by the pending model. Clear an incompatible pending speed change with a warning when switching models.
- Carry `service_tier` through Cloud message requests, preserving omission to inherit the thread tier and explicit null to clear it. Translate `default` to null and reject tier overrides on queued requests.

## Testing

Add tests for Cloud speed toggling, model-dependent speed choices, admission-time updates, and preserving the conversation tier when selecting a model. Extend request and wire tests to cover service-tier values, explicit clearing, and queue rejection.

GitOrigin-RevId: b4daa701f1fe29593d90a938e60cc20cb980298a

codex-rs/cloud-client/examples/attach.rs

@@ -32,6 +32,7 @@ async fn main() -> anyhow::Result<()> {
             turn_trigger: None,
             model: None,
             effort: None,
+            service_tier: None,
             mode: SubmissionMode::StartIfIdle,
             shared_access: false,
         }),

codex-rs/cloud-client/src/turns.rs

@@ -30,6 +30,8 @@ pub struct AddUserMessageRequest {
     /// Omit both to inherit the thread settings. A model alone uses its default effort.
     pub model: Option<String>,
     pub effort: Option<String>,
+    /// Omit to inherit the thread tier, or send an explicit null to clear it.
+    pub service_tier: Option<Option<String>>,
     pub mode: SubmissionMode,
     pub shared_access: bool,
 }
@@ -128,7 +130,9 @@ impl Client {
     ) -> Result<Admission, MutationError> {
         if request.thread_id.trim().is_empty()
             || request.client_user_message_id.trim().is_empty()
-            || ((request.model.is_some() || request.effort.is_some())
+            || ((request.model.is_some()
+                || request.effort.is_some()
+                || request.service_tier.is_some())
                 && matches!(request.mode, SubmissionMode::Queue))
             || !request.input.iter().any(|input| match input {
                 UserMessageInput::Text { text, .. } => !text.trim().is_empty(),
@@ -213,6 +217,15 @@ impl Client {
             }),
             model: request.model.clone(),
             effort: request.effort.clone(),
+            service_tier: request.service_tier.as_ref().map(|tier| {
+                use crate::activation_wire::nullable_string::Value;
+                crate::activation_wire::NullableString {
+                    value: Some(match tier {
+                        Some(tier) => Value::String(tier.clone()),
+                        None => Value::Null(crate::activation_wire::Empty {}),
+                    }),
+                }
+            }),
             thread_id: request.thread_id.clone(),
             turn_trigger: request.turn_trigger.clone(),
             access: request.shared_access.then_some(1),

codex-rs/cloud-client/src/turns_tests.rs

@@ -13,6 +13,7 @@ fn request() -> AddUserMessageRequest {
         turn_trigger: None,
         model: None,
         effort: None,
+        service_tier: None,
         mode: SubmissionMode::StartIfIdle,
         shared_access: true,
     }
@@ -45,12 +46,21 @@ async fn submission_preserves_admission_variants_and_wire_identity() {
         let mut fixture = fixture(response(vec![frame(&payload)], tonic::Status::ok(""))).await;
         let has_selection = !matches!(mode, SubmissionMode::Queue);
         let turn_trigger = (mode_number == 3).then(|| "user".to_owned());
+        let (service_tier, wire_tier) = match (mode_number, outcome_number) {
+            (3, 1) => (
+                Some(Some("ultrafast".into())),
+                message(/*tag*/ 20, &message(/*tag*/ 1, b"ultrafast")),
+            ),
+            (1, 2) => (Some(None), message(/*tag*/ 20, &message(/*tag*/ 2, b""))),
+            _ => (None, Vec::new()),
+        };
         let result = fixture
             .client
             .add_user_message(&AddUserMessageRequest {
                 turn_trigger,
                 model: has_selection.then(|| "selected-model".into()),
                 effort: has_selection.then(|| "high".into()),
+                service_tier,
                 mode,
                 ..request()
             })
@@ -106,6 +116,7 @@ async fn submission_preserves_admission_variants_and_wire_identity() {
                 ),
             ),
             if has_selection { model } else { vec![] },
+            wire_tier,
             message(/*tag*/ 23, b"t"),
             if mode_number == 3 {
                 message(/*tag*/ 25, b"user")
@@ -295,6 +306,11 @@ async fn invalid_input_never_sends_and_diagnostics_redact() {
             model: Some("selected-model".into()),
             ..request()
         },
+        AddUserMessageRequest {
+            mode: SubmissionMode::Queue,
+            service_tier: Some(Some("ultrafast".into())),
+            ..request()
+        },
         AddUserMessageRequest {
             input: vec![],
             ..request()

codex-rs/cloud-client/src/turns_wire.rs

@@ -11,6 +11,8 @@ pub(super) struct AddRequest {
     pub input: Option<Input>,
     #[prost(string, optional, tag = "12")]
     pub model: Option<String>,
+    #[prost(message, optional, tag = "20")]
+    pub service_tier: Option<crate::activation_wire::NullableString>,
     #[prost(string, tag = "23")]
     pub thread_id: String,
     #[prost(string, optional, tag = "25")]