Migrate all JS config and tools to TS and fix a number of type issues.
This required Node.js 22.18.0 or greater where [type-stripping was
enabled](https://nodejs.org/en/blog/release/v22.18.0) by default.
Given that Node 22 is the current LTS, I think it's ok to assume that
the user has a recent version of it.
Webpack currently requires the `--disable-interpret` flag to work,
should be fixed eventually with
https://github.com/webpack/webpack-cli/issues/4525.
`fast-glob` is replaced by `fs.globSync`, available in Node 22.0.0 or
greater.
- Move some scripts from `build` to new `tools` dir. Eventually i would
like to move all but let's do it step-by-step.
- Add dir to eslint and move the files into vars.
- Update docs accordingly.
- While updating docs I noticed we were incorrectly having `public/img`
path still in a few places. Replace those with the current
`public/assets/img`.
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Co-authored-by: Nanguan Lin <nanguanlin6@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>
