feat(api): add error field to PathInfo for stat failures

Cherry-picked from stainless-sdks/hypeman-typescript preview/feature/hypeman-cp.
Adds error field to PathInfo to communicate stat failures like permission denied.

Author: rgarcia

.stats.yml

@@ -1,4 +1,4 @@
 configured_endpoints: 30
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/kernel%2Fhypeman-962950583e6d0c5e72b547422e3cf0f6b9d00a7be1f1ad0b0430d5e742bf6e20.yml
-openapi_spec_hash: f5a6a0f94dded7dc78ddac6218034bb2
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/kernel%2Fhypeman-28e78b73c796f9ee866671ed946402b5d569e683c3207d57c9143eb7d6f83fb6.yml
+openapi_spec_hash: fce0ac8713369a5f048bac684ed34fc8
 config_hash: f65a6a2bcef49a9f623212f9de6d6f6f

src/resources/instances/instances.ts

@@ -282,6 +282,12 @@ export interface PathInfo {
    */
   exists: boolean;
 
+  /**
+   * Error message if stat failed (e.g., permission denied). Only set when exists is
+   * false due to an error rather than the path not existing.
+   */
+  error?: string | null;
+
   /**
    * True if this is a directory
    */