feat: use @cloudflare/vite-plugin to bundle worker

[ottomated]

This uses @cloudflare/vite-plugin only for building. Draft, currently it basically builds the ssr environment twice.

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[pkg-svelte-dev]

Install the latest version of @sveltejs/kit from 1d9c263:

pnpm add https://pkg.svelte.dev/@sveltejs/kit/c/1d9c263df3de09c6b402659fd0f665e7874b91fc

Open in pkg.svelte.dev: https://pkg.svelte.dev/repos/kit/pr/16811

[changeset-bot]

🦋 Changeset detected

Latest commit: 1d9c263

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@sveltejs/kit	Minor

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[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-kit-16811-svelte.vercel.app/