Code review guidance: more explicit about deferAfterAll (#18071)

Author: trask

.github/agents/code-review-and-fix.agent.md

@@ -233,6 +233,10 @@ Auto-fix boundaries:
     readers/writers/streams/response bodies).
     Do not apply this conversion in non-JUnit helper methods, `@BeforeAll`, or shared
     setup code.
+  - class-scoped resources created in `@BeforeAll` or other shared setup — prefer
+    `AutoCleanupExtension` with `deferAfterAll(...)` over nested `@AfterAll` cleanup
+    chains. Do not introduce or keep `AutoCleanupExtension` solely for a single
+    `deferAfterAll(...)` call — use a plain `@AfterAll` instead.
   - `hasAttributesSatisfying(...)` calls in test assertions — replace with
     `hasAttributesSatisfyingExactly(...)` because it is more precise (the non-exact
     variant silently ignores unexpected attributes)

.github/agents/knowledge/testing-general-patterns.md

@@ -33,10 +33,8 @@
   over wrapping most of the test body in try-with-resources.
 - For resources created in `@BeforeAll` or other class-scoped setup, prefer
   `AutoCleanupExtension` with `deferAfterAll(...)` over nested `@AfterAll` cleanup
-  chains. Prefer a single `@AfterAll` when `AutoCleanupExtension` is not otherwise present
-  or needed in the class. Do **not** introduce `AutoCleanupExtension` solely to call
-  `deferAfterAll(...)` once on a single resource — a plain `@AfterAll` is cleaner in that
-  case.
+  chains. Do not introduce or keep `AutoCleanupExtension` solely for a single
+  `deferAfterAll(...)` call — use a plain `@AfterAll` instead.
 - Reuse an existing `cleanup` extension when one is already in scope.
   Otherwise, add a `@RegisterExtension` field when the deferred-cleanup pattern improves
   clarity or avoids wrapping most of the test body.