Add realtime wire trace logs (#17838)

- Add trace-only wire logging for realtime websocket request/event text
payloads and the WebRTC call SDP request.
- Gate raw realtime logs behind
`RUST_LOG=codex_api::realtime_websocket::wire=trace` so normal logs stay
quiet.

---------

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

codex-rs/codex-api/src/endpoint/realtime_call.rs

@@ -119,6 +119,7 @@ impl<T: HttpTransport, A: AuthProvider> RealtimeCallClient<T, A> {
         session_config: RealtimeSessionConfig,
         extra_headers: HeaderMap,
     ) -> Result<RealtimeCallResponse, ApiError> {
+        trace!(target: "codex_api::realtime_websocket::wire", "realtime call request SDP: {sdp}");
         // WebRTC can begin inference as soon as the peer connection comes up, so the initial
         // session payload is sent with call creation. The sideband WebSocket still sends its normal
         // session.update after it joins.

codex-rs/codex-api/src/endpoint/realtime_websocket/methods.rs

@@ -45,6 +45,8 @@ use tracing::warn;
 use tungstenite::protocol::WebSocketConfig;
 use url::Url;
 
+const REALTIME_WIRE_LOG_TARGET: &str = "codex_api::realtime_websocket::wire";
+
 struct WsStream {
     tx_command: mpsc::Sender<WsCommand>,
     pump_task: tokio::task::JoinHandle<()>,
@@ -351,6 +353,7 @@ impl RealtimeWebsocketWriter {
             ));
         }
 
+        trace!(target: REALTIME_WIRE_LOG_TARGET, "realtime websocket request: {payload}");
         self.stream
             .send(Message::Text(payload.into()))
             .await
@@ -384,6 +387,7 @@ impl RealtimeWebsocketEvents {
 
             match msg {
                 Message::Text(text) => {
+                    trace!(target: REALTIME_WIRE_LOG_TARGET, "realtime websocket event: {text}");
                     if let Some(mut event) = parse_realtime_event(&text, self.event_parser) {
                         self.update_active_transcript(&mut event).await;
                         debug!(?event, "realtime websocket parsed event");