refactor: Move DiagramProvider to RootLayout for improved context management

app/layout.tsx

@@ -1,6 +1,8 @@
 import type { Metadata } from "next";
 import { Geist, Geist_Mono } from "next/font/google";
 import { Analytics } from "@vercel/analytics/react";
+import { DiagramProvider } from "@/contexts/diagram-context";
+
 import "./globals.css";
 
 const geistSans = Geist({
@@ -28,7 +30,8 @@ export default function RootLayout({
             <body
                 className={`${geistSans.variable} ${geistMono.variable} antialiased`}
             >
-                {children}
+                <DiagramProvider>{children}</DiagramProvider>
+
                 <Analytics />
             </body>
         </html>