feat(Composite.svelte): update layout interface

Refactor the Composite component to support a new layout format with additional customization through the customTailwind property. This change simplifies the way layouts are defined and provides greater flexibility for design customizations.

BREAKING CHANGE: The layout interface in Composite.svelte has been modified. Components that depend on the old layout structure may need to be updated.

src/routes/+page.svelte

@@ -2,14 +2,12 @@
 	import Composite from '$lib/components/Composite.svelte';
 
 	let componentsData = {
-		layout: `
-			grid-template-areas: 
-			"auth",
-				"header",
-				"main",
-				"footer"
-			grid-template-rows: 1fr 1fr auto;
-		`,
+		layout: {
+			areas: `"nav", "main", "footer"`,
+			gap: '10px',
+			columns: '1fr',
+			template: 'auto 1fr auto'
+		},
 		children: [
 			{
 				id: '1',