feat: add google gtag

src/app/layout.tsx

@@ -35,6 +35,18 @@ function RootLayout({ children }: { children: ReactNode }): ReactElement {
               `,
           }}
         />
+        {/* google */}
+        <script async src="https://www.googletagmanager.com/gtag/js?id=G-3VNFGQNP7Z" />
+        <script
+          dangerouslySetInnerHTML={{
+            __html: `
+              window.dataLayer = window.dataLayer || [];
+              function gtag(){dataLayer.push(arguments);}
+              gtag('js', new Date());
+              gtag('config', 'G-3VNFGQNP7Z');
+            `,
+          }}
+        />
       </body>
     </html>
   );