feat(ui): add ExchangeHeader component with correlation chain

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ui/src/pages/Exchanges/ExchangeHeader.tsx

@@ -0,0 +1,85 @@
+import { StatusDot, MonoText, Badge } from '@cameleer/design-system';
+import { useCorrelationChain } from '../../api/queries/correlation';
+import type { ExecutionDetail } from '../../components/ExecutionDiagram/types';
+
+interface ExchangeHeaderProps {
+  detail: ExecutionDetail;
+  onExchangeClick?: (executionId: string) => void;
+}
+
+type StatusVariant = 'success' | 'error' | 'running' | 'warning';
+type BadgeColor = 'success' | 'error' | 'running' | 'warning';
+
+function statusVariant(s: string): StatusVariant {
+  switch (s) {
+    case 'COMPLETED': return 'success';
+    case 'FAILED': return 'error';
+    case 'RUNNING': return 'running';
+    default: return 'warning';
+  }
+}
+
+function badgeColor(s: string): BadgeColor {
+  switch (s) {
+    case 'COMPLETED': return 'success';
+    case 'FAILED': return 'error';
+    case 'RUNNING': return 'running';
+    default: return 'warning';
+  }
+}
+
+function formatDuration(ms: number): string {
+  if (ms >= 60_000) return `${(ms / 1000).toFixed(0)}s`;
+  if (ms >= 1000) return `${(ms / 1000).toFixed(2)}s`;
+  return `${ms}ms`;
+}
+
+export function ExchangeHeader({ detail, onExchangeClick }: ExchangeHeaderProps) {
+  const { data: chainResult } = useCorrelationChain(detail.correlationId ?? null);
+  const chain = chainResult?.data;
+  const showChain = chain && chain.length > 1;
+
+  return (
+    <div style={{
+      display: 'flex', flexDirection: 'column', gap: '0.5rem',
+      padding: '0.75rem', borderBottom: '1px solid var(--border)',
+      background: 'var(--surface)', fontSize: '0.8125rem',
+    }}>
+      <div style={{ display: 'flex', alignItems: 'center', gap: '0.5rem', flexWrap: 'wrap' }}>
+        <StatusDot variant={statusVariant(detail.status)} />
+        <MonoText size="xs">{detail.exchangeId || detail.executionId}</MonoText>
+        <Badge label={detail.status === 'COMPLETED' ? 'OK' : detail.status} color={badgeColor(detail.status)} />
+        <span style={{ color: 'var(--text-muted)' }}>{detail.routeId}</span>
+        <span style={{ marginLeft: 'auto', fontFamily: 'var(--font-mono)', fontSize: '0.75rem' }}>
+          {formatDuration(detail.durationMs)}
+        </span>
+      </div>
+
+      {showChain && (
+        <div style={{ display: 'flex', gap: '0.25rem', flexWrap: 'wrap', alignItems: 'center' }}>
+          <span style={{ fontSize: '0.6875rem', color: 'var(--text-muted)', marginRight: '0.25rem' }}>
+            Correlated:
+          </span>
+          {chain.map((e) => (
+            <button
+              key={e.executionId}
+              onClick={() => onExchangeClick?.(e.executionId)}
+              style={{
+                background: e.executionId === detail.executionId ? 'var(--surface-active)' : 'var(--surface)',
+                border: '1px solid var(--border)',
+                borderRadius: '4px',
+                padding: '0.125rem 0.375rem',
+                cursor: 'pointer',
+                fontSize: '0.6875rem',
+                fontFamily: 'var(--font-mono)',
+                color: e.status === 'FAILED' ? 'var(--error)' : 'var(--text-secondary)',
+              }}
+            >
+              {e.executionId.slice(0, 8)}
+            </button>
+          ))}
+        </div>
+      )}
+    </div>
+  );
+}