fix: OS release prep - bootstrap script, deps, docs

- Fix bootstrap script (.env.example.local → .env.example)
- Fix @langchain/core version conflict (^1.0.1 → ^0.3.0)
- Add settings:open event listener for LocalKeyGate button
- Pin Next.js to 15.1.3 (was "latest")
- Default runtime to 'local' mode
- Remove desktop app references from UI text
- Rewrite MCP docs for web-only context
- Add SECURITY.md, CODE_OF_CONDUCT.md, CHANGELOG.md
- Add docs/README.md, docs/TROUBLESHOOTING.md
- Update README with platform support table

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/components/layout/ThreePanelLayout.tsx

@@ -112,6 +112,16 @@ export default function ThreePanelLayout() {
     return () => window.removeEventListener('keydown', handleKeyDown);
   }, [setNodesCollapsed, setChatCollapsed]);
 
+  // Listen for settings:open events (from LocalKeyGate)
+  useEffect(() => {
+    const handleSettingsOpen = (e: CustomEvent<{ tab?: SettingsTab }>) => {
+      setSettingsInitialTab(e.detail?.tab || 'apikeys');
+      setShowSettings(true);
+    };
+    window.addEventListener('settings:open', handleSettingsOpen as EventListener);
+    return () => window.removeEventListener('settings:open', handleSettingsOpen as EventListener);
+  }, []);
+
 
   // SSE connection for real-time updates
   useEffect(() => {