Brave (and maybe other browseres) refuse to set the 'User-Agent' header
in XMLHTTPRequests, and are vocal about this in the debug log. Since the
OpenAPI code generator always outputs a custom 'User-Agent' header, I've
added some JS code to strip that off when constructing an API client.
- Add a little confirmation overlay before deleting a job. This overlay
also shows information about whether the Shaman checkout directory
will be deleted or not.
- Send job updates to the web frontend when jobs are marked for
deletion, and when they are actually deleted.
- Respond to those updates, and handle some corner cases where job info
is missing (because it just got deleted).
This closes T99401.
