Update UI element size and change directory exclusion rule

This commit modifies the size of sun and moon icons in the mode-toggle UI and simplifies the space usage of a flex container in the site header. Furthermore, it updates the path pattern for the directory exclusion rule in tailwind configuration to exclude node_module from all directories.

apps/web/app/(marketing)/_components/site-header.tsx

@@ -18,10 +18,8 @@ export function SiteHeader(props: { user?: User | null }) {
           <SiteNavigation />
         </div>
 
-        <div className={'flex flex-1 items-center justify-end space-x-4'}>
-          <div className={'flex items-center'}>
-            <ModeToggle />
-          </div>
+        <div className={'flex flex-1 items-center justify-end space-x-2'}>
+          <ModeToggle />
 
           <SiteHeaderAccountSection user={props.user ?? null} />
         </div>