Add renewable EMA HTTP authentication and credential versioning (#49987)

## What changed

- Add `EmaAuthenticatedHttpClient` to cache and renew resource bearers, serialize concurrent renewals, and include authentication time in the request deadline. Confine bearers to the configured MCP endpoint and reject redirects.
- Return authentication-required errors for `401` responses without replaying MCP operations. Preserve a newer cached bearer when a delayed response rejects an older one.
- Add revocable request authority that cancels pending requests and ends response streams.
- Pin enterprise credentials to a persistent version advanced on save or deletion. Use short credential locks and invalidate rejected grants only when their record and version are still current, preserving newer logins.
- Hide keyring account identifiers from enterprise credential errors and traces while preserving authentication failure classification.

## Testing

Add tests for token expiry and renewal, endpoint confinement, redirects, request deadlines, revocation during renewal and streaming, delayed `401` responses, credential replacement and logout races, and credential error privacy.

GitOrigin-RevId: ee3e5cf7ecbba3d09e1ab29ed4fbb2a35eacc60d

codex-rs/exec-server/src/client/http_response_body_stream.rs

@@ -19,6 +19,7 @@ use tokio::runtime::Handle;
 use tokio::sync::OwnedSemaphorePermit;
 use tokio::sync::mpsc;
 use tokio::sync::mpsc::error::TrySendError;
+use tokio_util::sync::CancellationToken;
 use tracing::debug;
 
 use crate::client::ExecServerError;
@@ -75,6 +76,7 @@ enum HttpResponseBodyStreamInner {
 /// id until EOF or a terminal error.
 pub struct HttpResponseBodyStream {
     inner: HttpResponseBodyStreamInner,
+    cancellation: Option<CancellationToken>,
 }
 
 impl HttpResponseBodyStream {
@@ -93,6 +95,7 @@ impl HttpResponseBodyStream {
             inner: HttpResponseBodyStreamInner::Local {
                 body: Box::pin(body),
             },
+            cancellation: None,
         }
     }
 
@@ -101,6 +104,7 @@ impl HttpResponseBodyStream {
             inner: HttpResponseBodyStreamInner::Local {
                 body: Box::pin(response.bytes_stream()),
             },
+            cancellation: None,
         }
     }
 
@@ -118,14 +122,32 @@ impl HttpResponseBodyStream {
                 pending_eof: false,
                 closed: false,
             },
+            cancellation: None,
         }
     }
 
+    /// Ends this stream when its owning request authority is revoked.
+    pub fn cancel_on(mut self, cancellation: CancellationToken) -> Self {
+        self.cancellation = Some(cancellation);
+        self
+    }
+
     /// Receives the next response-body chunk.
     ///
     /// Returns `Ok(None)` at EOF and converts sequence gaps or stream-side
     /// stream errors into protocol errors.
     pub async fn recv(&mut self) -> Result<Option<Vec<u8>>, ExecServerError> {
+        let Some(cancellation) = self.cancellation.clone() else {
+            return self.recv_inner().await;
+        };
+        tokio::select! {
+            biased;
+            () = cancellation.cancelled() => Ok(None),
+            result = self.recv_inner() => result,
+        }
+    }
+
+    async fn recv_inner(&mut self) -> Result<Option<Vec<u8>>, ExecServerError> {
         match &mut self.inner {
             HttpResponseBodyStreamInner::Local { body } => match body.next().await {
                 Some(chunk) => match chunk {