refactor(store): split gatewayStore into specialized domain stores

Major restructuring:
- Split monolithic gatewayStore into 5 focused stores:
  - connectionStore: WebSocket connection and gateway lifecycle
  - configStore: quickConfig, workspaceInfo, MCP services
  - agentStore: clones, usage stats, agent management
  - handStore: hands, approvals, triggers, hand runs
  - workflowStore: workflows, workflow runs, execution

- Update all components to use new stores with selector pattern
- Remove

desktop/src/components/HandList.tsx

@@ -6,7 +6,7 @@
  */
 
 import { useEffect } from 'react';
-import { useGatewayStore, type Hand } from '../store/gatewayStore';
+import { useHandStore, type Hand } from '../store/handStore';
 import { Zap, Loader2, RefreshCw, CheckCircle, XCircle, AlertTriangle } from 'lucide-react';
 
 interface HandListProps {
@@ -42,7 +42,9 @@ const STATUS_LABELS: Record<Hand['status'], string> = {
 };
 
 export function HandList({ selectedHandId, onSelectHand }: HandListProps) {
-  const { hands, loadHands, isLoading } = useGatewayStore();
+  const hands = useHandStore((s) => s.hands);
+  const loadHands = useHandStore((s) => s.loadHands);
+  const isLoading = useHandStore((s) => s.isLoading);
 
   useEffect(() => {
     loadHands();