PhET-iO guide does not exist

[KatieWoe]

Device
Samsung
OS
Win 11
Browser
Chrome
Problem Description
For phetsims/qa#868
The link to the PhET-iO Guide leads to a 404 error.

[zepumph]

Thanks! There was an assumption that you needed an entry in phet-io-sim-specific to get a client guide, but now that is a generated and general resource for all sims, so I updated it so that you don't need a folder in phet-io-sim-specific to get that doc. This is the first sim of the new paradigm. While I was there I also simplified some elements in the process. This is cleanup that probably should have happened around the GAO publication process, but we didn't make the time for it. Now examples are in top level of each sim dir, and that is the only sim-specific file, since we don't need sim-specific images as far as I know.

[zepumph]

I discussed with @arouinfar and we agree about the current state of creating and maintaining client guides, I updated the README accordingly. I confirmed that friction is getting a phet-io guide now and has examples (the file and a row in the index). Closing