Switch entirely to bun for development

[lgarron]

bun has a lot of advantages for development:

• It can run TypeScript directly, allowing our scripts to be type-checked.
• It can run a lot of web-native APIs (e.g. web workers).
• It's faster than node to start up for scripts.
• It's faster than npm at installing dependencies (although npm is a lot better than it used to be).
• It has a bundler with an esbuild-inspired API, which could remove the need for a separate bundler.
• Much better APIs for e.g. process exec and testing.

Issues blocking complete adoption for cubing.js:

• Run playwright using bun: Fails to run Playwright browser automtation library oven-sh/bun#2492
• Install playwright using bun.
• For bundling:
  • Include import.meta.resolve(…) arguments in the source graph for bun build oven-sh/bun#2906
• Implement synchronous import.meta.resolve(…) oven-sh/bun#2472
• Dream: type bundling

We'll always want to test the build against node, but this can be one fairly simple test among all other tests.