feat(explorer): show Ethereum mainnet Etherscan links on attested transactions.

Render checkpoint batch attestation with per-layer mainnet tx links on the transaction detail page.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/components/checkpoint/MainnetAttestationPanel.tsx

@@ -0,0 +1,65 @@
+import Link from 'next/link'
+import { Card } from '@/libs/frontend-ui-primitives'
+import type { CheckpointMainnetAttestationLink } from '@/services/api/tokenAggregation'
+
+function shortHash(hash: string): string {
+  if (hash.length < 20) return hash
+  return `${hash.slice(0, 10)}…${hash.slice(-8)}`
+}
+
+export interface MainnetAttestationPanelProps {
+  batchId: string
+  batchTotalUsd?: string
+  links: CheckpointMainnetAttestationLink[]
+}
+
+export default function MainnetAttestationPanel({
+  batchId,
+  batchTotalUsd,
+  links,
+}: MainnetAttestationPanelProps) {
+  return (
+    <Card title="Ethereum mainnet attestation">
+      <p className="text-sm text-gray-600 dark:text-gray-400">
+        This Chain 138 transaction is included in checkpoint batch #{batchId}
+        {batchTotalUsd ? ` · USD ref ${batchTotalUsd}` : ''}.
+      </p>
+
+      {links.length === 0 ? (
+        <p className="mt-3 text-sm text-gray-500 dark:text-gray-400">
+          Attested on mainnet; Etherscan transaction links are indexing. Refresh in a minute or open the
+          checkpoint contracts on Etherscan.
+        </p>
+      ) : (
+        <ul className="mt-4 space-y-3">
+          {links.map((link) => (
+            <li
+              key={`${link.layer}:${link.mainnetTxHash}`}
+              className="rounded-2xl border border-primary-200/60 bg-primary-50/40 p-4 dark:border-primary-500/20 dark:bg-primary-950/20"
+            >
+              <div className="flex flex-wrap items-center gap-x-3 gap-y-2">
+                <span className="text-sm font-medium text-gray-900 dark:text-white">
+                  {link.label || link.layer}
+                </span>
+                <Link
+                  href={link.mainnetExplorerUrl}
+                  target="_blank"
+                  rel="noopener noreferrer"
+                  className="font-mono text-sm text-primary-600 hover:underline dark:text-primary-400"
+                >
+                  {shortHash(link.mainnetTxHash)} ↗
+                </Link>
+              </div>
+              {(link.meta?.role || link.meta?.uetr) && (
+                <div className="mt-2 flex flex-wrap gap-3 text-xs text-gray-500 dark:text-gray-400">
+                  {link.meta.role ? <span>role: {link.meta.role}</span> : null}
+                  {link.meta.uetr ? <span>UETR: {link.meta.uetr}</span> : null}
+                </div>
+              )}
+            </li>
+          ))}
+        </ul>
+      )}
+    </Card>
+  )
+}

frontend/src/pages/transactions/[hash].tsx

@@ -20,6 +20,7 @@ import PaginationControls from '@/components/common/PaginationControls'
 import SectionTabs, { type SectionTab } from '@/components/common/SectionTabs'
 import { getGruCatalogPosture } from '@/services/api/gruCatalog'
 import { assessTransactionCompliance } from '@/utils/transactionCompliance'
+import MainnetAttestationPanel from '@/components/checkpoint/MainnetAttestationPanel'
 import {
   tokenAggregationApi,
   type CheckpointTxAttestationSnapshot,
@@ -504,6 +505,14 @@ export default function TransactionDetailPage() {
             </div>
           </Card>
 
+          {checkpointAttestation ? (
+            <MainnetAttestationPanel
+              batchId={checkpointAttestation.batchId}
+              batchTotalUsd={checkpointAttestation.batchTotalUsd}
+              links={checkpointAttestation.etherscanLinks ?? []}
+            />
+          ) : null}
+
           <SectionTabs tabs={tabs} activeTab={activeTab} onChange={setActiveTab} className="mb-6" />
 
           {activeTab === 'evidence' && complianceAssessment ? (

frontend/src/services/api/tokenAggregation.ts

@@ -37,6 +37,16 @@ export interface CheckpointTransferUsdLine {
   priceSource?: string
 }
 
+export interface CheckpointMainnetAttestationLink {
+  layer: string
+  label: string
+  mainnetTxHash: string
+  mainnetExplorerUrl: string
+  contractAddress?: string
+  logIndex?: number
+  meta?: Record<string, string>
+}
+
 export interface CheckpointTxAttestationSnapshot {
   txHash: string
   included: boolean
@@ -50,6 +60,11 @@ export interface CheckpointTxAttestationSnapshot {
     priceSource?: string
     transfers?: CheckpointTransferUsdLine[]
   } | null
+  etherscanLinks?: CheckpointMainnetAttestationLink[]
+  etherscan?: {
+    base?: string
+    txUrlTemplate?: string
+  }
   source?: string
 }