Direct side feedback mechanism

> Part of recommendations from user research report in #1496

## Recommendations

> Implement a feedback system directly on the website, allowing users to report problems or suggest improvements as they browse.

And:

> The idea of actively engaging the community through up-to-date information and tools such as surveys, feedback directly on the site, and the ability to evaluate the usefulness of pages could provide a channel for obtaining direct opinions from users and continuously improving the site.

Related: #392

## Working on this

Start by reviewing the feasibility of this. Possibly this could be as simple as using GitHub Discussions – create a Discussions thread per page of the site, link to it at the bottom of the pages? Similar to [Giscus](https://giscus.app/) but without the "on-page commenting" aspect.

Start by reviewing the recommendations in issue #1496 and the related issue #392. Compare the feasibility of GitHub Discussions links per page with the Giscus-style approach described here. Done means documenting a decided feedback mechanism and its scope, or implementing the agreed approach.

Written by the indexing model from the issue text.