feat: social graph features

components/site-header.tsx

@@ -24,6 +24,7 @@
 
 import Link from "next/link";
 import { ReadingSettings } from "@/components/reading-settings";
+import { NotificationBell } from "@/components/notification-bell";
 import { useAuth } from "@/components/auth/auth-provider";
 
 export function SiteHeader() {
@@ -53,6 +54,13 @@ export function SiteHeader() {
             <ReadingSettings />
           </div>
         ) : null}
+        {/* Notification bell — signed-in users only (anonymous viewers get
+            the reading-settings gear above instead). */}
+        {!loading && user ? (
+          <div className="absolute right-2 top-1/2 -translate-y-1/2">
+            <NotificationBell />
+          </div>
+        ) : null}
       </div>
     </header>
   );