fix(desktop): component cleanup + dead code removal + DeerFlow ai-elements

- ChatArea: DeerFlow ai-elements annotations for accessibility
- Conversation: remove unused Context, simplify message rendering
- Delete dead modules: audit-logger.ts, gateway-reconnect.ts
- Replace console.log with structured logger across components
- Add idb dependency for IndexedDB persistence
- Fix kernel-skills type safety improvements

desktop/package.json

@@ -43,6 +43,7 @@
     "clsx": "^2.1.1",
     "dompurify": "^3.3.3",
     "framer-motion": "^12.38.0",
+    "idb": "^8.0.3",
     "lucide-react": "^0.577.0",
     "react": "^19.2.4",
     "react-dom": "^19.2.4",