fix: improve duration formatting (Xm Ys) and truncate exchange IDs

- formatDuration and formatDurationShort now show Xm Ys for durations >= 60s (e.g. "5m 21s" instead of "321s") and 1 decimal for 1-60s range ("6.7s" instead of "6.70s")
- Exchange ID column shows last 8 chars with ellipsis prefix; full ID on hover, copies to clipboard on click

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

ui/src/pages/AgentHealth/AgentHealth.tsx

@@ -8,6 +8,7 @@ import {
 } from '@cameleer/design-system';
 import type { Column, FeedEvent, LogEntry, ButtonGroupItem } from '@cameleer/design-system';
 import styles from './AgentHealth.module.css';
+import sectionStyles from '../../styles/section-card.module.css';
 import logStyles from '../../styles/log-panel.module.css';
 import { useAgents, useAgentEvents } from '../../api/queries/agents';
 import { useApplicationLogs } from '../../api/queries/logs';
@@ -353,7 +354,7 @@ export default function AgentHealth() {
 
       {/* Application config bar */}
       {appId && appConfig && (
-        <div className={styles.configBar}>
+        <div className={`${sectionStyles.section} ${styles.configBar}`}>
           {configEditing ? (
             <>
               <div className={styles.configField}>
@@ -569,7 +570,7 @@ export default function AgentHealth() {
           )}
         </div>
 
-        <div className={styles.eventCard}>
+        <div className={`${sectionStyles.section} ${styles.eventCard}`}>
           <div className={styles.eventCardHeader}>
             <span className={styles.sectionTitle}>Timeline</span>
             <div className={logStyles.headerActions}>