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>

src/components/Settings/index.tsx

@@ -254,6 +254,7 @@ export default function Settings() {
 
   // System settings
   const [filterOutOnionRelays, setFilterOutOnionRelays] = useState(storage.getFilterOutOnionRelays())
+  const [graphQueriesEnabled, setGraphQueriesEnabled] = useState(storage.getGraphQueriesEnabled())
 
   // Messaging settings
   const [preferNip44, setPreferNip44] = useState(storage.getPreferNip44())
@@ -738,6 +739,25 @@ export default function Settings() {
                 }}
               />
             </SettingItem>
+            <SettingItem>
+              <div>
+                <Label htmlFor="graph-queries-enabled" className="text-base font-normal">
+                  {t('Graph query optimization')}
+                </Label>
+                <p className="text-sm text-muted-foreground">
+                  {t('Use graph queries for faster follow/thread loading on supported relays')}
+                </p>
+              </div>
+              <Switch
+                id="graph-queries-enabled"
+                checked={graphQueriesEnabled}
+                onCheckedChange={(checked) => {
+                  storage.setGraphQueriesEnabled(checked)
+                  setGraphQueriesEnabled(checked)
+                  dispatchSettingsChanged()
+                }}
+              />
+            </SettingItem>
           </AccordionContent>
           </AccordionItem>
         </NavigableAccordionItem>