fix(retry): treat request-level errors as retryable

[tusharmath]

Summary

Treat request-level reqwest errors as retryable, fixing the peer closed connection without sending TLS close_notify error from the ChatGPT codex endpoint.

Context

Requests to https://chatgpt.com/backend-api/codex/responses were failing permanently with:

peer closed connection without sending TLS close_notify

This error surfaces as a reqwest::Error with is_request() == true. The existing retry check only covered is_timeout() and is_connect(), so these request-level transport failures were never retried.

Changes

• Added || e.is_request() to is_req_transport_error — a one-line fix
• Added one test that simulates a peer dropping the connection and verifies it's retried

Testing

cargo insta test --accept -p forge_repo

Links

• rustls docs on unexpected EOF: https://docs.rs/rustls/latest/rustls/manual/_03_howto/index.html#unexpected-eof