add vue config to eslint, and adopt (mostly) standard JS style

[rsek]

i noticed that some v-for directives were missing their keys, so i've added vue's official eslint plugin/config to hint us towards their "best practices".

update: added (mostly) standardjs for prettier and eslint on top of this, and ran autofix for both.

i've diverged on two rules:

• tabs, which are actual tab characters for accessibility reasons. and so that folks can configure their tab width as desired, instead of forcing it on them
• explicit return types. it's a sensible rule, but right now the errors are noisy and require a bunch of manual intervention to resolve. i'd be happy to revisist this after i get all my wacky refactors merged.

[rsek]

whoops, looks like my local main wasn't up to date when i made this branch. that should now be fixed. it's introduced some CI complains, however -- i'll look at those next.

[ben]

Well the tests pass and the system loads, so it's probably okay. Super hard to do a detailed review of something like this. 😁