chore: proper client extraction (#6996)

codex-rs/codex-client/src/error.rs

@@ -0,0 +1,29 @@
+use http::HeaderMap;
+use http::StatusCode;
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum TransportError {
+    #[error("http {status}: {body:?}")]
+    Http {
+        status: StatusCode,
+        headers: Option<HeaderMap>,
+        body: Option<String>,
+    },
+    #[error("retry limit reached")]
+    RetryLimit,
+    #[error("timeout")]
+    Timeout,
+    #[error("network error: {0}")]
+    Network(String),
+    #[error("request build error: {0}")]
+    Build(String),
+}
+
+#[derive(Debug, Error)]
+pub enum StreamError {
+    #[error("stream failed: {0}")]
+    Stream(String),
+    #[error("timeout")]
+    Timeout,
+}