Add editable own profile + navigation fixes

- ProfileView shows edit form when viewing own profile
- publishProfile (kind 0) added to nostr lib
- Sidebar name/avatar opens own profile
- Back button in edit mode cancels form; outside edit mode navigates back
- goBack safeguard: falls back to feed if previousView === currentView
- Fix ThreadView crash when selectedNote is null
- Tighten feed filter for base64 blobs and protocol messages

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

src/components/thread/ThreadView.tsx

@@ -45,7 +45,8 @@ function RootNote({ event }: { event: NDKEvent }) {
 export function ThreadView() {
   const { selectedNote, goBack } = useUIStore();
   const { loggedIn } = useUserStore();
-  const event = selectedNote!;
+  if (!selectedNote) { goBack(); return null; }
+  const event = selectedNote;
 
   const [replies, setReplies] = useState<NDKEvent[]>([]);
   const [loading, setLoading] = useState(true);