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/WorkflowHistory.tsx

@@ -8,7 +8,7 @@
  */
 
 import { useState, useEffect, useCallback } from 'react';
-import { useGatewayStore, type Workflow, type WorkflowRun } from '../store/gatewayStore';
+import { useWorkflowStore, type Workflow, type WorkflowRun } from '../store/workflowStore';
 import {
   ArrowLeft,
   Clock,
@@ -113,7 +113,9 @@ function RunCard({ run, index }: RunCardProps) {
 }
 
 export function WorkflowHistory({ workflow, onBack }: WorkflowHistoryProps) {
-  const { loadWorkflowRuns, cancelWorkflow, isLoading } = useGatewayStore();
+  const loadWorkflowRuns = useWorkflowStore((s) => s.loadWorkflowRuns);
+  const cancelWorkflow = useWorkflowStore((s) => s.cancelWorkflow);
+  const isLoading = useWorkflowStore((s) => s.isLoading);
   const [runs, setRuns] = useState<WorkflowRun[]>([]);
   const [isRefreshing, setIsRefreshing] = useState(false);
   const [cancellingRunId, setCancellingRunId] = useState<string | null>(null);