[Proposal] Support web workers (`worker-src`) via `workerDomains` on `McpUiResourceCsp`

[hydrosquall]

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

MCP apps can load several file types via resourceDomains ( img-src, script-src, style-src, font-src, media-src ), but it cannot load web-workers

Describe the solution you'd like

I'd like to set a new property workerDomains on the McpUiResourceCsp interface , and use this to list permitted domains (or the inlined blob: option) for serving web-worker code.

Describe alternatives you've considered

• We could render our own iframe inside the main iframe
• We avoid using features that use web-workers
• We could add worker-src to the list of resources supported by resourceDomains, but web-workers are complex enough from a security perspective that hosts that don't want to support them should be able to reject this type without impacting the other static resource types.