James,
Do you have any kind of logging enabled on your server? Even with the basic console-capture module, you can see contexts start and stop.
Using the demo base as an example, I removed the context xml file for our JAAS Test webapp. Console output/log is as follows:
2019-10-22 13:58:48.878:INFO:oejsh.ContextHandler:Scanner-0: Stopped o.e.j.w.WebAppContext@48c76607{JAAS Test,/test-jaas,null,UNAVAILABLE}{PATH\TO\JETTY\jetty-distribution-9.4.22.v20191022\demo-base\webapps/test-jaas.war}
By contrast, replacing the context XML re-deploys the webapp.
Console output/log is as follows:
2019-10-22 14:04:08.260:WARN::Scanner-0: test-jaas webapp is deployed. DO NOT USE IN PRODUCTION!
2019-10-22 14:04:08.280:INFO:oejsh.ContextHandler:Scanner-0: Started o.e.j.w.WebAppContext@168b947{JAAS Test,/test-jaas,file:///C:/Users/cleve/AppData/Local/Temp/jetty-0_0_0_0-8080-test-jaas_war-_test-jaas-any-10326669567532780878.dir/webapp/,AVAILABLE}{PATH\TO\JETTY\jetty-distribution-9.4.22.v20191022\demo-base\webapps/test-jaas.war}
If you have logging set up you should easily be able to capture this and do what you want with the info. If there are any errors/warnings you will see them in the log when trying to deploy/remove the context in question.
As for a console command, there isn't one really. Editing the Context XML or the WAR will automatically reload the context and will be accompanied by log information. You can find more about Hot Deployment like this in the documentation.
Best,
Chris