Report diagnostic upload failures (#39287)

## Why

Submitting a diagnostic report could appear successful without confirming that Sentry accepted the upload, leaving callers unable to detect transport or HTTP failures.

## What changed

- Send report envelopes through the route-aware HTTP client and await the response.
- Reject redirects, propagate transport and non-success HTTP responses, and include the full error chain in upload JSON-RPC errors.
- Add structured logs for upload attempts, successes, and failures without including report contents.

## Testing

Added coverage for successful uploads, rejected responses, blocked redirects, transport failures, and app-server JSON-RPC error reporting.

GitOrigin-RevId: 07b5cfccd7a65f35d51a720537d2cd8962ed6cdb

codex-rs/app-server/tests/suite/v2/feedback.rs

@@ -0,0 +1,48 @@
+use std::time::Duration;
+
+use anyhow::Result;
+use app_test_support::TestAppServer;
+use codex_app_server_protocol::RequestId;
+use pretty_assertions::assert_eq;
+use serde_json::json;
+use tokio::time::timeout;
+use wiremock::Mock;
+use wiremock::MockServer;
+use wiremock::ResponseTemplate;
+use wiremock::matchers::method;
+
+#[tokio::test]
+async fn feedback_upload_reports_transport_failure_as_json_rpc_error() -> Result<()> {
+    let proxy = MockServer::start().await;
+    Mock::given(method("CONNECT"))
+        .respond_with(ResponseTemplate::new(503))
+        .expect(1)
+        .mount(&proxy)
+        .await;
+    let proxy_uri = proxy.uri();
+    let mut app_server = TestAppServer::builder()
+        .with_env_overrides(&[
+            ("HTTPS_PROXY", Some(proxy_uri.as_str())),
+            ("https_proxy", Some(proxy_uri.as_str())),
+            ("NO_PROXY", Some("")),
+            ("no_proxy", Some("")),
+        ])
+        .build_initialized()
+        .await?;
+
+    let request_id = app_server
+        .send_raw_request(
+            "feedback/upload",
+            Some(json!({ "classification": "bug", "includeLogs": false })),
+        )
+        .await?;
+    let error = timeout(
+        Duration::from_secs(15),
+        app_server.read_stream_until_error_message(RequestId::Integer(request_id)),
+    )
+    .await??;
+
+    assert_eq!(error.error.code, -32603);
+    assert!(error.error.message.contains("failed to upload feedback"));
+    Ok(())
+}

codex-rs/app-server/tests/suite/v2/mod.rs

@@ -31,6 +31,7 @@ mod experimental_api;
 mod experimental_feature_list;
 mod external_agent_config;
 mod external_agent_import_sync;
+mod feedback;
 mod fs;
 mod git_attribution;
 mod guardian_v2;