🔧 Repository: Enable `listDeprecations` for Maintainer Owned Workspaces

### 📜 Description

The Community Plugin Maintainers own roughly 40+ plugins, to help keep them well maintained we are looking for some help form the Backstage Community to clean up deprecated code.

### 📑 How

The process for this will be as follows:

1. Pick a workspace from the list below
2. Create a branch with your work selected workspace in the name, for example `workspace-name/list-deprecations`
3. Navigate to the workspace and open it's `bcp.json` file
4. Add this below any existing properties: `"listDeprecations": true`
5. Then run `yarn install` followed by `yarn backstage-cli repo list-deprecations`
6. This will list out any usages of deprecated code with what is needed to remove them
7. Make the needed changes
8. Commit your changes to your branch from step 2
9. Publish your branch and create a PR
10. Follow the normal contribution guide: https://github.com/backstage/community-plugins/blob/main/CONTRIBUTING.md

### Examples

This PR has examples of the change and the CI has output of the messages you can use if you need help: https://github.com/backstage/community-plugins/pull/5938

### Workspaces

> [!NOTE]
> Thanks to all various Community Members who have helped move this forward!!!! 🚀
>
> This list has been updated to show the workspaces that still need to be opted into this as of 2026-02-08

- [x] jenkins
- [x] lighthouse
- [ ] periskop
- [ ] shortcuts
- [ ] tech-radar
- [ ] todo
- [ ] vault
- [ ] xcmetrics

Choose one unchecked workspace, then open its bcp.json and review the existing properties. Add listDeprecations, run yarn install followed by yarn backstage-cli repo list-deprecations, and use the output to identify the required cleanup. Done means the reported deprecated-code usages are addressed and the branch is ready for a pull request following CONTRIBUTING.md.

Written by the indexing model from the issue text.