Add grammar checker to automated tests

[polymutex]

This seems cool: https://writewithharper.com/docs/integrations/language-server

It also has VSCode integration: https://writewithharper.com/docs/integrations/visual-studio-code

We already have a spellchecker, and this would take it to the next level. I've probably made some grammatical mistakes or used suboptimal wording in attribute definitions.

[polymutex]

@darrylyeo Do you have suggestions on how to implement this, specifically around the unit test framework to use?

Right now Walletbeat is mostly just typechecking-time checks, build-time checks, linters, and a few runtime checks. It would be nice to be able to introduce test-time checks that run after the linters do. For example, I'm thinking harper-js could run on the markdown strings (after the {{WALLET_NAME}} replacements have occurred). This implies some type of unit test that can import files from data and run checks on them. What framework would you recommend for that?

[polymutex]

https://docs.astro.build/en/guides/testing/ suggests Vitest for unit testing, and Playwright for end-to-end tests that involve fully-rendered HTML.

[polymutex]

Note to self: Add grammar checking for ref labels and explanations.