- Linter packages are updated to the last versions supported before
    deprecating Node 16. (so, these will be updated again soon.)

- Extensions for VS Code are working again.
    (recent auto-updates dropped support for the versions we were on)

Moving these support files directly into the kpi repo makes it easier
to:

- edit the files -- less indirection; can include linter updates as part
    of regular commits during feature work)

- keep dependencies up to date -- there are ways to manage these npm
    packages between multiple repos in lockstep but it's a lot more
    complicated to do it like that

- support VS Code -- there's an unstated assumption among the standard
    extensions that your language- and build-related npm packages are
    installed at the top level of your projects. it's one more reason
    an extension might be broken at any given time. your options are:

    (1) install once, at the root level of the project, and rule out
        that this is a problem

    (2) install in your nested module and install a copy with a
        matching version at the root level, too, update them in lockstep
        and cross your fingers

    shout out to Sublime / Neovim for not having this problem

Show the prompt that lets VS Code run the local TypeScript version in
your workspace, so it matches the output of `npx tsc`.

---

The error in formGallery/utils.ts is weird. This StackOverflow snippet
checks if something is an instance of an Object or Array. TS2358 aptly
notices that the right-hand side of

   value instanceof Object || value instanceof Array

will never be reached, since an array is also an instanceof Object.

So this could become

   value instanceof Object

…but to preserve the meaning of the code, I've just switched their
order around.

---

Updated TS while I'm at it, since the code still builds without an issue
and it's nice to keep on top of it.