Stop logging every Responses WebSocket event (#29432)

## Why

Every successful Responses WebSocket event currently produces three
local log records: the full payload at TRACE, an OpenTelemetry log
event, and an OpenTelemetry trace event.

On busy threads these records fill the 1,000-row log partition in
seconds and cause continuous SQLite insert-and-prune churn.

Related to
https://openai.slack.com/archives/C095U48JNL9/p1782128972644209

## What changed

- Stop logging each successful Responses WebSocket payload at TRACE.
- Stop emitting `codex.websocket_event` as OpenTelemetry log and trace
events.
- Keep WebSocket event counters, duration metrics, response timing
metrics, parsing, and error handling.

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

@@ -668,7 +668,6 @@ async fn run_websocket_response_stream(
 
         match message {
             Message::Text(text) => {
-                trace!("websocket event: {text}");
                 if let Some(wrapped_error) = parse_wrapped_websocket_error_event(&text)
                     && let Some(error) =
                         map_wrapped_websocket_error_event(wrapped_error, text.to_string())