svelte-check breaking changes v4

[dummdidumm]

Loose collection of things we should do for v4:

• make TypeScript a peer dependency

Timing:

• after we investigated Volar
• with Svelte 5?

[benmccann]

Potentially https://github.com/sveltejs/language-tools/issues/2391

[dummdidumm]

• Possibly chokidar v4 is out by then and we should check whether or not to switch to it. By the looks of it it will be ESM only, so we need change our output to be ESM, too. But that sounds like a good thing to do either way; and likely harmless since svelte-check is meant to be used as a command line tool where that doesn't matter.
• Checks which minimum Node version to support. Probably 18

[dummdidumm]

#2420

[dummdidumm]

Idea for svelte-preprocess (would address #2391):

• keep it in language-server, but load it through await with try-catch
• make it external in rollup build config in svelte-check, which means the fallback doesn't kick in when using svelte-check

PR's related to major:

• #2401
• #2433
• #1860