Add app-server v2 thread realtime API (#12715)

Add experimental `thread/realtime/*` v2 requests and notifications, then
route app-server realtime events through that thread-scoped surface with
integration coverage.

---------

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

codex-rs/app-server-protocol/src/protocol/v2.rs

@@ -46,6 +46,7 @@ use codex_protocol::protocol::PatchApplyStatus as CorePatchApplyStatus;
 use codex_protocol::protocol::RateLimitSnapshot as CoreRateLimitSnapshot;
 use codex_protocol::protocol::RateLimitWindow as CoreRateLimitWindow;
 use codex_protocol::protocol::ReadOnlyAccess as CoreReadOnlyAccess;
+use codex_protocol::protocol::RealtimeAudioFrame as CoreRealtimeAudioFrame;
 use codex_protocol::protocol::RejectConfig as CoreRejectConfig;
 use codex_protocol::protocol::SessionSource as CoreSessionSource;
 use codex_protocol::protocol::SkillDependencies as CoreSkillDependencies;
@@ -2551,6 +2552,157 @@ pub struct ErrorNotification {
     pub turn_id: String,
 }
 
+/// EXPERIMENTAL - thread realtime audio chunk.
+#[derive(Serialize, Deserialize, Debug, Default, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeAudioChunk {
+    pub data: String,
+    pub sample_rate: u32,
+    pub num_channels: u16,
+    pub samples_per_channel: Option<u32>,
+}
+
+impl From<CoreRealtimeAudioFrame> for ThreadRealtimeAudioChunk {
+    fn from(value: CoreRealtimeAudioFrame) -> Self {
+        let CoreRealtimeAudioFrame {
+            data,
+            sample_rate,
+            num_channels,
+            samples_per_channel,
+        } = value;
+        Self {
+            data,
+            sample_rate,
+            num_channels,
+            samples_per_channel,
+        }
+    }
+}
+
+impl From<ThreadRealtimeAudioChunk> for CoreRealtimeAudioFrame {
+    fn from(value: ThreadRealtimeAudioChunk) -> Self {
+        let ThreadRealtimeAudioChunk {
+            data,
+            sample_rate,
+            num_channels,
+            samples_per_channel,
+        } = value;
+        Self {
+            data,
+            sample_rate,
+            num_channels,
+            samples_per_channel,
+        }
+    }
+}
+
+/// EXPERIMENTAL - start a thread-scoped realtime session.
+#[derive(Serialize, Deserialize, Debug, Default, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeStartParams {
+    pub thread_id: String,
+    pub prompt: String,
+    #[ts(optional = nullable)]
+    pub session_id: Option<String>,
+}
+
+/// EXPERIMENTAL - response for starting thread realtime.
+#[derive(Serialize, Deserialize, Debug, Default, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeStartResponse {}
+
+/// EXPERIMENTAL - append audio input to thread realtime.
+#[derive(Serialize, Deserialize, Debug, Default, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeAppendAudioParams {
+    pub thread_id: String,
+    pub audio: ThreadRealtimeAudioChunk,
+}
+
+/// EXPERIMENTAL - response for appending realtime audio input.
+#[derive(Serialize, Deserialize, Debug, Default, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeAppendAudioResponse {}
+
+/// EXPERIMENTAL - append text input to thread realtime.
+#[derive(Serialize, Deserialize, Debug, Default, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeAppendTextParams {
+    pub thread_id: String,
+    pub text: String,
+}
+
+/// EXPERIMENTAL - response for appending realtime text input.
+#[derive(Serialize, Deserialize, Debug, Default, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeAppendTextResponse {}
+
+/// EXPERIMENTAL - stop thread realtime.
+#[derive(Serialize, Deserialize, Debug, Default, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeStopParams {
+    pub thread_id: String,
+}
+
+/// EXPERIMENTAL - response for stopping thread realtime.
+#[derive(Serialize, Deserialize, Debug, Default, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeStopResponse {}
+
+/// EXPERIMENTAL - emitted when thread realtime startup is accepted.
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeStartedNotification {
+    pub thread_id: String,
+    pub session_id: Option<String>,
+}
+
+/// EXPERIMENTAL - raw non-audio thread realtime item emitted by the backend.
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeItemAddedNotification {
+    pub thread_id: String,
+    pub item: JsonValue,
+}
+
+/// EXPERIMENTAL - streamed output audio emitted by thread realtime.
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeOutputAudioDeltaNotification {
+    pub thread_id: String,
+    pub audio: ThreadRealtimeAudioChunk,
+}
+
+/// EXPERIMENTAL - emitted when thread realtime encounters an error.
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeErrorNotification {
+    pub thread_id: String,
+    pub message: String,
+}
+
+/// EXPERIMENTAL - emitted when thread realtime transport closes.
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ThreadRealtimeClosedNotification {
+    pub thread_id: String,
+    pub reason: Option<String>,
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
 #[serde(rename_all = "camelCase")]
 #[ts(export_to = "v2/")]