feat: route control buttons reflect current route state

Buttons are disabled based on route state: Started disables
Start/Resume, Stopped disables Stop/Suspend/Resume, Suspended
disables Start/Suspend. State looked up from catalog API.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/pages/Exchanges/ExchangeHeader.tsx

@@ -1,9 +1,10 @@
 import { useMemo } from 'react';
 import { useNavigate } from 'react-router';
 import { GitBranch, Server, RotateCcw, FileText } from 'lucide-react';
-import { StatusDot, MonoText, Badge } from '@cameleer/design-system';
+import { StatusDot, MonoText, Badge, useGlobalFilters } from '@cameleer/design-system';
 import { useCorrelationChain } from '../../api/queries/correlation';
 import { useAgents } from '../../api/queries/agents';
+import { useRouteCatalog } from '../../api/queries/catalog';
 import { useAuthStore } from '../../auth/auth-store';
 import type { ExecutionDetail } from '../../components/ExecutionDiagram/types';
 import { attributeBadgeColor } from '../../utils/attribute-color';
@@ -44,11 +45,27 @@ function formatDuration(ms: number): string {
 
 export function ExchangeHeader({ detail, onCorrelatedSelect, onClearSelection }: ExchangeHeaderProps) {
   const navigate = useNavigate();
+  const { timeRange } = useGlobalFilters();
   const { data: chainResult } = useCorrelationChain(detail.correlationId ?? null);
   const chain = chainResult?.data;
   const showChain = chain && chain.length > 1;
   const attrs = Object.entries(detail.attributes ?? {});
 
+  // Look up route state from catalog
+  const { data: catalog } = useRouteCatalog(timeRange.start.toISOString(), timeRange.end.toISOString());
+  const routeState = useMemo(() => {
+    if (!catalog) return undefined;
+    for (const app of catalog as any[]) {
+      if (app.appId !== detail.applicationId) continue;
+      for (const route of app.routes || []) {
+        if (route.routeId === detail.routeId) {
+          return (route.routeState ?? 'started') as 'started' | 'stopped' | 'suspended';
+        }
+      }
+    }
+    return undefined;
+  }, [catalog, detail.applicationId, detail.routeId]);
+
   // Look up agent state for icon coloring + route control capability
   const { data: agents } = useAgents(undefined, detail.applicationId);
   const { agentState, hasRouteControl, hasReplay } = useMemo(() => {
@@ -114,6 +131,7 @@ export function ExchangeHeader({ detail, onCorrelatedSelect, onClearSelection }:
         <RouteControlBar
           application={detail.applicationId}
           routeId={detail.routeId}
+          routeState={routeState}
           hasRouteControl={hasRouteControl}
           hasReplay={hasReplay}
           agentId={detail.instanceId}

ui/src/pages/Exchanges/RouteControlBar.tsx

@@ -8,6 +8,7 @@ import styles from './RouteControlBar.module.css';
 interface RouteControlBarProps {
   application: string;
   routeId: string;
+  routeState?: 'started' | 'stopped' | 'suspended';
   hasRouteControl: boolean;
   hasReplay: boolean;
   agentId?: string;
@@ -25,7 +26,13 @@ const ROUTE_ACTIONS: { action: RouteAction; label: string; icon: typeof Play; co
   { action: 'resume',  label: 'Resume',  icon: PlayCircle, colorClass: styles.success },
 ];
 
-export function RouteControlBar({ application, routeId, hasRouteControl, hasReplay, agentId, exchangeId, inputHeaders, inputBody }: RouteControlBarProps) {
+const ACTION_DISABLED: Record<string, Set<RouteAction>> = {
+  started:   new Set(['start', 'resume']),
+  stopped:   new Set(['stop', 'suspend', 'resume']),
+  suspended: new Set(['start', 'suspend']),
+};
+
+export function RouteControlBar({ application, routeId, routeState, hasRouteControl, hasReplay, agentId, exchangeId, inputHeaders, inputBody }: RouteControlBarProps) {
   const { toast } = useToast();
   const sendRouteCommand = useSendRouteCommand();
   const replayExchange = useReplayExchange();
@@ -34,6 +41,7 @@ export function RouteControlBar({ application, routeId, hasRouteControl, hasRepl
   const [pendingConfirm, setPendingConfirm] = useState<RouteAction | null>(null);
 
   const busy = sendingAction !== null;
+  const disabledActions = ACTION_DISABLED[routeState ?? 'started'] ?? new Set();
 
   const handleRouteClick = useCallback((action: RouteAction) => {
     if (action === 'stop' || action === 'suspend') {
@@ -98,7 +106,7 @@ export function RouteControlBar({ application, routeId, hasRouteControl, hasRepl
             <button
               key={action}
               className={`${styles.segment} ${colorClass}`}
-              disabled={busy}
+              disabled={busy || disabledActions.has(action)}
               onClick={() => handleRouteClick(action)}
               title={`${label} route ${routeId}`}
             >