feat: revamp documentation pages with new components, layout, and visuals

Introduced enhanced MDX components (cards, callouts, tabs, accordions, steps) for better content presentation. Redesigned the homepage with new sections highlighting features, tech stack, and quick access links. Updated the global CSS to use Catppuccin theme. Added branded visuals like the Memegoat logo and SVG. Improved metadata, localization (French), and search functionality.

documentation/src/lib/layout.shared.tsx

@@ -1,9 +1,32 @@
 import type { BaseLayoutProps } from "fumadocs-ui/layouts/shared";
+import {Image} from "fumadocs-core/framework";
 
 export function baseOptions(): BaseLayoutProps {
 	return {
 		nav: {
-			title: "My App",
+			title: (
+				<span className="flex items-center gap-2 font-bold text-xl">
+					<Image
+						src="/memegoat-color.svg"
+						alt="Memegoat Logo"
+						width={64}
+						height={64}
+						className="w-8 h-8"
+					/>
+					<span>Memegoat</span>
+				</span>
+			),
 		},
+		links: [
+			{
+				text: "Documentation",
+				url: "/docs",
+				active: "nested-url",
+			},
+			{
+				text: "GitHub",
+				url: "https://git.yidhra.fr/Mathis/memegoat",
+			},
+		],
 	};
 }