Plugin should auto-clean the @tmp/jfrog directory

### Is your feature request related to a problem? Please describe.

Intermittently, our pipelines running `jf rt build-publish` via the Jenkins JFrog plugin failed with `cipher: message authentication failure` or `401, Token failed verification: parse` errors.

The issue stemmed from two pipelines sharing a single workspace to speed up incremental builds. Occasionally, they reused an old `@tmp/jfrog/` configuration from a previous run. Because the Jenkins JFrog plugin never auto-cleans the `@tmp/jfrog` directory, these stale configurations caused the build-publish command to fail. If the plugin automatically cleaned this directory, the issue wouldn’t occur.

### Describe the solution you'd like to see

The Jenkins JFrog plugin should automatically clean up old `@tmp/jfrog` configurations after builds, or provide a configurable option to do so. This would prevent stale configuration reuse and eliminate related authentication errors.

### Describe alternatives you've considered

We implemented a custom post-cleanup step in each pipeline that automatically removes the `@tmp/jfrog` directory after each run of a pipeline that uses the Jenkins JFrog plugin.

We also considered using the `hudson.model.WorkspaceCleanupThread` system property, but it doesn’t support per-run cleanup, so it wasn’t a viable option.

### Additional context

_No response_

Start by tracing the Jenkins JFrog plugin path that runs `jf rt build-publish` and creates configuration under the workspace `@tmp/jfrog/` directory. Check how per-run cleanup could occur after builds and verify that stale configurations are removed without disrupting shared-workspace builds; the issue names no source files or tests, so repository exploration is required.

Written by the indexing model from the issue text.