Claiming namespace [across-systems]

### Namespace

across-systems

### Ownership

- [x] The namespace is not currently owned on Open VSX (verify by a search on [open-vsx.org](https://open-vsx.org))

### Account Age

- [x] The GitHub ID making this request has at least 12 months of public history

### VS Code Publisher with Repo

- [x] The namespace is also a publisher account on the VS Code Marketplace (check by browsing https://marketplace.visualstudio.com/publishers/{publisher}) and has an extension published there with a repo specified in its package.json file.

### VS Code Publisher without Repo

- [ ] The namespace is also a publisher account on the VS Code Marketplace and does not have published extensions or has published extensions with no GitHub repos.

### Not a VS Code Marketplace Publisher

- [ ] The namespace is not a publisher account on the VS Code Marketplace

### All Other Cases

- [ ] You are unable to provide the inputs required in the three options above. This option will take the longest to process.

### Claim evidence

- Marketplace publisher: https://marketplace.visualstudio.com/publishers/across-systems
- Extension: across-systems.acr-viewer-vscode
- package.json "repository": https://github.com/acrossreport/acr-viewer-vscode
- I am the owner/admin of the "acrossreport" GitHub organization, logged in as HisaAraki.

Start by checking the across-systems namespace on open-vsx.org, then verify the Marketplace publisher page and the extension's package.json repository link. Confirm the supplied ownership and account-age evidence; the work is done when the namespace claim is validated and processed.

Written by the indexing model from the issue text.