Add structured telemetry for response retries (#38452)

## What changed

- Emit trace-safe `codex.retry` events immediately before retry delays, including the attempt number, selected delay, retry layer, and operation.
- Cover HTTP requests, sampling streams, remote compaction, and sampling connection recovery. Track connection-recovery attempts separately from the stream retry budget.
- Add integration coverage for retry timing and terminal behavior across HTTP, SSE, WebSocket, and remote-compaction paths, including rate limits, overloads, connection failures, and `Retry-After` inputs.

GitOrigin-RevId: dae38900a0579cf8ba062c3f3d90ee61851c1c99

codex-rs/codex-client/Cargo.toml

@@ -11,6 +11,7 @@ futures = { workspace = true }
 http = { workspace = true }
 rand = { workspace = true }
 tokio = { workspace = true, features = ["macros", "rt", "time", "sync"] }
+tracing = { workspace = true }
 
 [lints]
 workspace = true