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/ApprovalsPanel.tsx

@@ -8,11 +8,8 @@
  */
 
 import { useState, useEffect, useCallback } from 'react';
-import {
-  useGatewayStore,
-  type Approval,
-  type ApprovalStatus,
-} from '../store/gatewayStore';
+import { useHandStore } from '../store/handStore';
+import type { Approval, ApprovalStatus } from '../store/handStore';
 import {
   CheckCircle,
   XCircle,
@@ -297,8 +294,10 @@ function EmptyState({ filter }: { filter: FilterStatus }) {
 // === Main ApprovalsPanel Component ===
 
 export function ApprovalsPanel() {
-  const { approvals, loadApprovals, respondToApproval, isLoading } =
-    useGatewayStore();
+  const approvals = useHandStore((s) => s.approvals);
+  const loadApprovals = useHandStore((s) => s.loadApprovals);
+  const respondToApproval = useHandStore((s) => s.respondToApproval);
+  const isLoading = useHandStore((s) => s.isLoading);
   const [filter, setFilter] = useState<FilterStatus>('all');
   const [processingId, setProcessingId] = useState<string | null>(null);