Add profile view with clickable names/avatars

- ProfileView shows avatar, bio, nip05, website, recent notes
- Clicking any name or avatar navigates to their profile
- Add fetchUserNotes to nostr lib (kind 1 by author)
- Add openProfile action + selectedPubkey to UI store
- Back button returns to feed

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/App.tsx

@@ -2,6 +2,7 @@ import { Sidebar } from "./components/sidebar/Sidebar";
 import { Feed } from "./components/feed/Feed";
 import { RelaysView } from "./components/shared/RelaysView";
 import { SettingsView } from "./components/shared/SettingsView";
+import { ProfileView } from "./components/profile/ProfileView";
 import { useUIStore } from "./stores/ui";
 
 function App() {
@@ -14,6 +15,7 @@ function App() {
         {currentView === "feed" && <Feed />}
         {currentView === "relays" && <RelaysView />}
         {currentView === "settings" && <SettingsView />}
+        {currentView === "profile" && <ProfileView />}
       </main>
     </div>
   );