fix: align all pages with design system mocks — stat cards, tables, detail panels

Dashboard: correct stat card labels (Exchanges/Success Rate/Errors/Throughput/Latency p99),
add detail text, trends, sparklines on all cards, Agent column, LIVE badge,
expanded detail panel with Agent/Correlation/Timestamp, "Open full details" link.

Agent Health: per-group meta (TPS/routes) in GroupCard header, proper HTML table
with column headers for instance list.

Agent Instance: stat card detail props (heap info, start date), scope trail with
inline status/version/routes badges.

Routes: 5th In-Flight stat card, enriched stat card props (detail/trend/sparkline),
SLA threshold line on latency chart.

Exchange Detail: Agent stat box in header.

Also: vite proxy CORS fix, cross-env dev scripts.

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

ui/src/pages/ExchangeDetail/ExchangeDetail.tsx

@@ -68,6 +68,10 @@ export default function ExchangeDetail() {
               <div className={styles.headerStatLabel}>Duration</div>
               <div className={styles.headerStatValue}>{detail.durationMs}ms</div>
             </div>
+            <div className={styles.headerStat}>
+              <div className={styles.headerStatLabel}>Agent</div>
+              <div className={styles.headerStatValue}>{detail.agentId}</div>
+            </div>
             <div className={styles.headerStat}>
               <div className={styles.headerStatLabel}>Processors</div>
               <div className={styles.headerStatValue}>{countProcessors(detail.processors || detail.children || [])}</div>