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/stores/ui.ts

@@ -26,6 +26,9 @@ export const useUIStore = create<UIState>((set, get) => ({
   setView: (currentView) => set({ currentView }),
   openProfile: (pubkey) => set((s) => ({ currentView: "profile", selectedPubkey: pubkey, previousView: s.currentView as View })),
   openThread: (note, from) => set({ currentView: "thread", selectedNote: note, previousView: from }),
-  goBack: () => set((s) => ({ currentView: s.previousView, selectedNote: null })),
+  goBack: () => set((s) => ({
+    currentView: s.previousView !== s.currentView ? s.previousView : "feed",
+    selectedNote: null,
+  })),
   toggleSidebar: () => set((s) => ({ sidebarCollapsed: !s.sidebarCollapsed })),
 }));