Missing wait events (gap analysis)

Hi hi

Many tools that implement wait event analysis, when visualizing samples with "wait_event is null" use green color and "CPU" (perhaps, it started with RDS Performance Insights and PASH Viewer and, I suppose, originally came from the Oracle world, and now I see it in many more places).

I don't have any concerns with green color, but always had a feeling that "coalesce(wait_event, 'CPU')" is an assumption that can make analysis inaccurate, because there may be a lot of places in the code that are not covered by wait events, but technically should -- and such places cannot be named "CPU".

I asked Claude Code to analyze Postgres source code and find such places, that we could potentially cover with more wait events. Here is the first result: https://github.com/NikolayS/postgres/blob/claude/cpu-asterisk-wait-events-01CyiYYMMcFMovuqPqLNcp8T/WAIT_EVENTS_ANALYSIS.md

Before moving forward with proposals of specific patches, I wanted to hear opinions -- does it make sense to work in this direction?