Add graph query optimization for faster social graph operations

- Add GraphQueryService for NIP-XX graph queries
- Add GraphCacheService for IndexedDB caching of results
- Optimize FollowedBy component with graph queries
- Add graph query support to ThreadService
- Add useFetchFollowGraph hook
- Add graph query toggle in Settings > System
- Bump version to v0.4.0

🤖 Generated with [Claude Code](https://claude.ai/code)

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "smesh",
-  "version": "0.3.1",
+  "version": "0.4.0",
   "description": "A user-friendly Nostr client for exploring relay feeds",
   "private": true,
   "type": "module",