Add websocket telemetry metrics and labels (#10316)

Summary
- expose websocket telemetry hooks through the responses client so
request durations and event processing can be reported
- record websocket request/event metrics and emit runtime telemetry
events that the history UI now surfaces
- improve tests to cover websocket telemetry reporting and guard runtime
summary updates


<img width="824" height="79" alt="Screenshot 2026-01-31 at 5 28 12 PM"
src="https://github.com/user-attachments/assets/ea9a7965-d8b4-4e3c-a984-ef4fdc44c81d"
/>

codex-rs/Cargo.lock

@@ -1427,6 +1427,7 @@ dependencies = [
  "multimap",
  "once_cell",
  "openssl-sys",
+ "opentelemetry_sdk",
  "os_info",
  "predicates",
  "pretty_assertions",
@@ -1451,6 +1452,7 @@ dependencies = [
  "thiserror 2.0.17",
  "time",
  "tokio",
+ "tokio-tungstenite",
  "tokio-util",
  "toml 0.9.5",
  "toml_edit 0.24.0+spec-1.1.0",
@@ -1778,6 +1780,7 @@ dependencies = [
  "strum_macros 0.27.2",
  "thiserror 2.0.17",
  "tokio",
+ "tokio-tungstenite",
  "tracing",
  "tracing-opentelemetry",
  "tracing-subscriber",