feat(layout): remove prerender from layout.svelte and create +layout.…

…server.ts

The prerender flag was removed from layout.svelte and moved to a new
file layout.server.ts. This change is part of a refactor to improve
the structure of the codebase.

src/routes/+layout.server.ts

@@ -0,0 +1 @@
+export const prerender = true;

src/routes/+layout.svelte

@@ -1,6 +1,4 @@
 <script lang='ts'>
-	export const prerender = true;
-
 	import 'uno.css';
 	import '@unocss/reset/normalize.css';