feat(ui): redesign ExchangeHeader with info bar, arrows, and navigation

- Always shows exchange info row: status dot, badge, ID, route, app, duration
- Correlation chain: arrow connectors between nodes, route name + duration per node
- Click on correlated exchange navigates to /exchanges/:app/:route/:exchangeId
- Compact styling with bg-raised background, proper visual hierarchy
- Horizontal scroll for long correlation chains

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

ui/src/pages/Exchanges/ExchangeHeader.module.css

@@ -1,61 +1,95 @@
+/* ── Header bar above diagram ─────────────────────────────────────────────── */
+
 .header {
   display: flex;
   flex-direction: column;
-  gap: 0.5rem;
-  padding: 0.75rem;
+  gap: 0;
   border-bottom: 1px solid var(--border);
-  background: var(--surface);
-  font-size: 0.8125rem;
+  background: var(--bg-raised, var(--surface));
+  flex-shrink: 0;
 }
 
-.summary {
+/* ── Exchange info row ────────────────────────────────────────────────────── */
+
+.info {
   display: flex;
   align-items: center;
   gap: 0.5rem;
-  flex-wrap: wrap;
+  padding: 0.5rem 0.75rem;
+  font-size: 0.75rem;
+  border-bottom: 1px solid var(--border-subtle);
+}
+
+.separator {
+  width: 1px;
+  height: 14px;
+  background: var(--border);
+  flex-shrink: 0;
+}
+
+.route {
+  font-weight: 600;
+  color: var(--text-primary);
+}
+
+.app {
+  color: var(--text-muted);
 }
 
 .duration {
   margin-left: auto;
   font-family: var(--font-mono);
-  font-size: 0.75rem;
+  font-size: 0.6875rem;
+  font-weight: 600;
+  color: var(--text-secondary);
 }
 
-/* ── Correlation chain ────────────────────────────────────────────────────── */
+/* ── Correlation chain row ────────────────────────────────────────────────── */
 
 .chain {
   display: flex;
-  flex-direction: row;
   align-items: center;
-  gap: 8px;
-  padding-top: 8px;
-  margin-top: 4px;
-  border-top: 1px solid var(--border-subtle);
-  flex-wrap: wrap;
+  gap: 0;
+  padding: 0.375rem 0.75rem;
+  overflow-x: auto;
 }
 
 .chainLabel {
-  font-size: 10px;
-  font-weight: 600;
+  font-size: 9px;
+  font-weight: 700;
   text-transform: uppercase;
-  letter-spacing: 0.5px;
+  letter-spacing: 0.8px;
   color: var(--text-muted);
-  margin-right: 4px;
+  margin-right: 0.5rem;
+  flex-shrink: 0;
+}
+
+.chainEntry {
+  display: inline-flex;
+  align-items: center;
+}
+
+.chainArrow {
+  color: var(--text-faint, var(--text-muted));
+  font-size: 10px;
+  margin: 0 4px;
+  flex-shrink: 0;
 }
 
 .chainNode {
   display: inline-flex;
   align-items: center;
   gap: 4px;
-  padding: 4px 10px;
+  padding: 3px 8px;
   border-radius: var(--radius-sm);
   border: 1px solid var(--border-subtle);
-  font-size: 11px;
+  font-size: 10px;
   font-family: var(--font-mono);
   cursor: pointer;
   background: var(--bg-surface);
   color: var(--text-secondary);
   transition: all 0.12s;
+  white-space: nowrap;
 }
 
 .chainNode:hover {
@@ -68,6 +102,7 @@
   border-color: var(--amber-light);
   color: var(--amber-deep);
   font-weight: 600;
+  cursor: default;
 }
 
 .chainNodeSuccess {
@@ -86,8 +121,11 @@
   border-left: 3px solid var(--warning);
 }
 
-.chainMore {
-  color: var(--text-muted);
-  font-size: 11px;
-  font-style: italic;
+.chainRoute {
+  font-weight: 500;
+}
+
+.chainDuration {
+  color: var(--text-muted);
+  font-size: 9px;
 }