Describe the problem

It is common for vite plugins to offer config options via first parameter to the initializer function.
With svelte-kit you currently have to define all options in svelte.config.js, even those for vite-plugin-svelte that are very vite specific.

To allow for a more logical grouping (vite related options in vite.config.js, svelte related options in svelte.config.js) it would be great if this was possible for kit as well.

Describe the proposed solution

export default defineConfig({
  plugins:[kit({
   ...kit_config,
   vitePluginSvelte: {... vite plugin svelte options}
  })]
})

the kit config gets merged with the values from svelte.config.js and vitePluginSvelte is passed to the initializer function of v-p-s.

Alternatives considered

keep it as is.

Importance

nice to have

Additional Information

with the next release, vite-plugin-svelte is going to change the location for it's options in svelte.config.js to vitePlugin. sveltejs/vite-plugin-svelte#389