chore(deps-dev): upgrading out of date dev dependencies

[erunion]

This updates all of our out of date development dependencies in order to resolve a number of issues being reported by npm audit and Dependabot. I have also uninstalled Vitest because we do not have any tests in this repository.

Before

$ npm outdated
Package                Current  Wanted  Latest  Location                            Depended by
@babel/eslint-parser   7.26.10  7.28.5  7.28.5  node_modules/@babel/eslint-parser   marketplace
@babel/preset-react     7.26.3  7.28.5  7.28.5  node_modules/@babel/preset-react    marketplace
@readme/eslint-config   14.6.0  14.8.1  14.8.1  node_modules/@readme/eslint-config  marketplace
eslint                  8.57.1  8.57.1  9.39.0  node_modules/eslint                 marketplace
prettier                 3.5.3   3.6.2   3.6.2  node_modules/prettier               marketplace
vitest                   3.0.9   3.2.4   4.0.6  node_modules/vitest                 marketplace

After

$ npm outdated
Package  Current  Wanted  Latest  Location             Depended by
eslint    8.57.1  8.57.1  9.39.0  node_modules/eslint  marketplace

[rafegoldberg]

(just out of curiosity, why is eslint still listed as outdated? should we update it? or did that prove too annoying?)

[erunion]

Upgrading to v9 is a real pain and nontrivial

[erunion]

@rafegoldberg Check out readmeio/standards#993 for some work I started on it earlier this year. The amount of work required to upgrade it to v9 is partially why we've been slowly adopting Biome in our open source projects (aside from it being fast and having a huge improvement of TS linting over @typescript-eslint).