RFC: Migrate to Vite+, second attempt.

[cpojer]

Note: I figured I'll follow-up with a solution so you can take a look at it and make a decision, but I'm fine either way if you don't want to adopt Vite+ at this time.

The initial PR was reverted with this feedback:

don't want to lock us into requiring an additional vp global CLI to work in the repo. (I'm sure that's fine for teams but extra friction for OSS). Didn't realize that was required.
seemed like knip struggled with vp a bit with the extra config, and wasn't confident we could keep that file maintainable over time.

I changed this PR so that package.json scripts stick around, and pnpm can be used same as vp in this repo. It still uses the local vp binary part of the vite-plus package, but should no longer require a new global.

I was too conservative on the knip setup changes at first, and changed it to be less work to maintain.

Ema is astro core maintainer and biome lead maintainer, so we have a bit of a preference for Biome and I haven't had any problems with it yet in this repo.

I can't argue with that! However, this repo only uses Biome for linting, and is using Prettier for formatting. If you'd like to proceed with this PR, I can either leave it as is or disable linting in Vite+ and bring back Biome. It still unifies and standardizes a lot of other tooling.

---

Original PR:

This PR moves the flue repo to Vite+. Please see https://viteplus.dev/ for how to set up Vite+.

• Package management is done through vp install, using pnpm under the hood.
• Biome was migrated to Oxlint/Oxfmt, configured via vite.config.ts, and should be used via vp check --fix.
• Turbo was replaced by Vite Task.
• Use vite-plus/pack instead of tsdown.
• Use vite-plus/test instead of vitest.
• Added a pre-commit hook that runs vp check.
• Removed apps/www/package-lock.json, which I assume was there by accident.
• There was a small number of changes due to the formatter change.

Overall, this gives a common toolchain to flue with a single vite.config.ts configuration file, and everything is fast.

[cpojer]

cc @FredKSchott

[FredKSchott]

not a priority atm, can revisit in a couple of weeks, appreciate the contribution!