[vsimko]

Summary

• Add an isolated two-core leader/follower integration test for aborting an in-progress ReplicationHandler fetch.
• Use a large stored-only payload to keep the transfer active, poll details.follower.isReplicating, issue abortfetch, and verify the fetch stops without installing the leader document.
• Exercise the same behavior in standalone and BasicAuth integration jobs; all resources are disposable cores cleaned up by the fixture.

Closes #259 if the pinned Solr 8.11.4, 9.11.0, and 10.1.0 matrix passes.

Validation

• CI will run the Node 20/22/24 and pinned Solr matrix. The test has a bounded active-state wait and bounded post-abort wait.