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/App.tsx

@@ -14,7 +14,8 @@ import { AgentOnboardingWizard } from './components/AgentOnboardingWizard';
 import { HandApprovalModal } from './components/HandApprovalModal';
 import { TopBar } from './components/TopBar';
 import { DetailDrawer } from './components/DetailDrawer';
-import { useGatewayStore, type HandRun } from './store/gatewayStore';
+import { useConnectionStore } from './store/connectionStore';
+import { useHandStore, type HandRun } from './store/handStore';
 import { useTeamStore } from './store/teamStore';
 import { useChatStore } from './store/chatStore';
 import { getStoredGatewayToken } from './lib/gateway-client';
@@ -53,7 +54,10 @@ function App() {
   const [showApprovalModal, setShowApprovalModal] = useState(false);
   const [teamViewMode, setTeamViewMode] = useState<'collaboration' | 'orchestrator'>('collaboration');
 
-  const { connect, hands, approveHand, loadHands } = useGatewayStore();
+  const connect = useConnectionStore((s) => s.connect);
+  const hands = useHandStore((s) => s.hands);
+  const approveHand = useHandStore((s) => s.approveHand);
+  const loadHands = useHandStore((s) => s.loadHands);
   const { activeTeam, setActiveTeam, teams } = useTeamStore();
   const { setCurrentAgent, newConversation } = useChatStore();
   const { isNeeded: onboardingNeeded, isLoading: onboardingLoading, markCompleted } = useOnboarding();