"Klay" Layout Option Missing in Azure Digital Twins Explorer

## GitHub Issue: "Klay" Layout Option Missing in Azure Digital Twins Explorer

**Describe the bug**
The "Klay" layout option is no longer available in the Azure Digital Twins Explorer UI. This issue affects all of my Azure Digital Twins instances, and the option has disappeared from the "Choose Layout" menu in the graph viewer. I have used the Klay layout for years, and the problem began suddenly without any changes to my models, twins, or environment.

**To Reproduce**
Steps to reproduce the behavior:
1. Open Azure Digital Twins Explorer (hosted or local).
2. Connect to any Azure Digital Twins instance.
3. Open the graph viewer and click the "Choose Layout" button.
4. Observe that the "Klay" option is missing from the list of available layouts (only options like Cola, Dagre, and fCoSE are shown).

**Expected behavior**
The "Klay" layout option should appear in the "Choose Layout" menu, as documented and as it has for years.

**Screenshots & Console Output**
- The option is missing from the UI across all environments and browsers.
- There are multiple errors in the Chrome DevTools console, some of which appear related to loading JavaScript modules or services for the layouts.
(If needed, I can provide screenshots and specific error messages.)

**Additional context**
- This issue is not related to changes in my models or twins; it occurs across all Digital Twins instances and environments.
- I have tried clearing the browser cache, reloading, and using different browsers, but the issue persists.
- The problem started suddenly and affects all users in my organization.
- I suspect this is due to a frontend issue, such as a failed JavaScript module load or a problem with the KLayJS dependency.
- I have checked the [known issues documentation] but did not find any reference to this problem.

**Environment:**
- Azure Digital Twins Explorer (hosted version at explorer.digitaltwins.azure.net and local builds)
- Chrome (latest), Edge (latest)
- Multiple Azure Digital Twins instances

**Request**
Please investigate if there is a problem with the KLayJS integration, a recent update, or a service outage that could cause the "Klay" layout option to disappear. Let me know if you need further details, screenshots, or error logs.

Thank you!

Citations:
[1] https://github.com/Azure-Samples/digital-twins-explorer

The issue identifies the graph viewer's Choose Layout menu and a suspected KLayJS integration, but no source file or test. Start by tracing how layout options and JavaScript modules are loaded; done means Klay appears again in hosted and local builds without related console loading errors.

Written by the indexing model from the issue text.