Performance monitoring

SKS says a key metric is:

How long does it take to go from clicking on an analysis template to the bottom output node grid coming up

We could possibly get this now from clever mining on NGINX logs, but another option is to track it with some kind of instrumentation.

Could then have a performance monitoring page etc

The issue names no files, tests, or entry points. First clarify whether the metric should come from NGINX logs or application instrumentation, then define the monitoring page and the exact start and end events that determine when the work is done.

Written by the indexing model from the issue text.