maintenance: Add clean scripts

[lsr-explore]

Add clean script to the package.json

Note from slack

ok I take back what I said about the clean script not being a big enough deal to warrant an issue, might as well make it an issue to queue it lol
(this isn't only about windows support, it's also about an edge case I realized due to how astro stores preferences in the same folder that it stores a bunch of generated assets in) (edited)