Change formatter to Biome

[gwhitney]

See the draft PR #623: @ysulyma recommends that we switch from Prettier to Biome. I am definitely not in love with Prettier, but there is some amount of switchover cost, represented for example by the fact that a couple of source files change layout by virtue of the switchover, and a couple need some new "ignore this non-conformant layout" flags inserted, although mostly they all stay identical. In favor of the switchover is the report that switching from Prettier to Biome reduces linting time from 6 seconds to about 0.2 seconds. Yuri may have suggestions for other advantages to Biome. He also recommends removing ESLint altogether, although I am unclear whether Biome can also do the job that ESLint is doing, or if there is another tool to replace ESLint, or if the recommendation is that what ESLint is doing is unworthwhile when using Biome to do what it can do.

[ysulyma]

In favor of the switchover is the report that switching from Prettier to Biome reduces linting time from 6 seconds to about 0.2 seconds.

Replacing Prettier and ESLint by Biome would achieve such a speedup. Prettier only takes about 0.8 seconds, but it's easier to convert.

I am unclear whether Biome can also do the job that ESLint is doing

Yes, Biome is a combined formatter + linter, intended to replace both Prettier and ESLint. (In my PR I turned the linting functionality off and only enabled the formatter.) However, their Vue support is relatively recent.