feat: add ErrorProps to generated types

[Rich-Harris]

Adds an ErrorProps type to ./$types:

<script lang="ts">
	import type { ErrorProps } from './$types.js';

	const { error }: ErrorProps = $props();
</script>

<h1>{error.message}</h1>

Ideally this would be injected automatically, just like PageProps is today, for zero-config type safety.

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[pkg-svelte-dev]

Install the latest version of @sveltejs/kit from d3087f4:

pnpm add https://pkg.svelte.dev/@sveltejs/kit/c/d3087f472dac7f850ae2a2a5f2003f3a50fcd1ae

Open in pkg.svelte.dev: https://pkg.svelte.dev/repos/kit/pr/16272

[changeset-bot]

🦋 Changeset detected

Latest commit: d3087f4

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-16272-svelte.vercel.app/

[dummdidumm]

Is there a way to make it only appear for +error.svelte files?

[Rich-Harris]

Not without having multiple files per route (./$types.d.ts, ./$error-types.d.ts, ./$layout-types.d.ts), but we already decided against that when we created PageProps alongside LayoutProps