Reduce explorer cache churn without extending freshness windows

app/address/[address]/components/AddressGraph.tsx

@@ -81,7 +81,7 @@ export function AddressGraph({ address }: { address: string }) {
               <div><dt className="text-muted">Indexed transactions</dt><dd className="mt-1 text-secondary font-mono">{selected.peer.txCount.toLocaleString('en-US')}</dd></div>
             </> : null}
           </dl>
-          <Link href={`/address/${selected.id}`} className="mt-5 inline-flex rounded border border-cipher-border px-3 py-2 text-xs font-mono text-primary hover:bg-cipher-hover">Open address →</Link>
+          <Link href={`/address/${selected.id}`} prefetch={false} className="mt-5 inline-flex rounded border border-cipher-border px-3 py-2 text-xs font-mono text-primary hover:bg-cipher-hover">Open address →</Link>
         </div> : <div><h3 className="text-sm font-semibold text-primary">Inspect a connection</h3><p className="mt-2 text-xs leading-relaxed text-muted">Select a node or choose an address below. Its details stay open while you explore.</p></div>}
         <div className="mt-5 border-t border-cipher-border pt-4">
           <label htmlFor="connection-search" className="text-xs text-muted">Find a displayed address or label</label>

app/address/[address]/components/AddressHeroCard.tsx

@@ -36,8 +36,8 @@ export function AddressHeroCard({ data, priceData, crossChain, totalTxCount }: {
         </dl>
       </div>
       {(funding || (crossChain && crossChain.totalSwaps > 0)) && <div className="flex flex-wrap gap-x-8 gap-y-3 border-t border-cipher-border px-5 sm:px-7 py-4 text-xs text-muted">
-        {funding && <p>First funding <Link href={`/tx/${funding.txid}`} className="ml-2 text-secondary underline underline-offset-4 hover:text-primary">{funding.amountZec.toLocaleString('en-US', { maximumFractionDigits: 8 })} {CURRENCY} ↗</Link>
-          {funding.isCoinbase ? ' · Mining reward' : funding.funderAddress ? <> · From <Link className="text-secondary hover:text-primary" href={`/address/${funding.funderAddress}`}>{funding.funderLabel || `${funding.funderAddress.slice(0, 6)}…${funding.funderAddress.slice(-4)}`}</Link></> : null}
+        {funding && <p>First funding <Link href={`/tx/${funding.txid}`} prefetch={false} className="ml-2 text-secondary underline underline-offset-4 hover:text-primary">{funding.amountZec.toLocaleString('en-US', { maximumFractionDigits: 8 })} {CURRENCY} ↗</Link>
+          {funding.isCoinbase ? ' · Mining reward' : funding.funderAddress ? <> · From <Link className="text-secondary hover:text-primary" href={`/address/${funding.funderAddress}`} prefetch={false}>{funding.funderLabel || `${funding.funderAddress.slice(0, 6)}…${funding.funderAddress.slice(-4)}`}</Link></> : null}
         </p>}
         {crossChain && crossChain.totalSwaps > 0 && <p>Bridge records <span className="ml-2 font-mono text-secondary">{crossChain.totalSwaps.toLocaleString('en-US')}</span> · {crossChain.entryCount} in / {crossChain.exitCount} out</p>}
       </div>}

app/address/[address]/components/AddressSummary.tsx

@@ -36,7 +36,7 @@ export function AddressSummary({ data, totalTxCount }: AddressSummaryProps) {
     if (funding.funderLabel && funding.funderAddress) {
       return (
         <Link
-          href={`/address/${funding.funderAddress}`}
+          href={`/address/${funding.funderAddress}`} prefetch={false}
           className="text-cipher-gold hover:text-primary transition-colors"
         >
           {funding.funderLabel}
@@ -46,7 +46,7 @@ export function AddressSummary({ data, totalTxCount }: AddressSummaryProps) {
     if (funding.funderAddress) {
       return (
         <Link
-          href={`/address/${funding.funderAddress}`}
+          href={`/address/${funding.funderAddress}`} prefetch={false}
           className="text-cipher-gold hover:text-primary transition-colors"
         >
           {shortAddr(funding.funderAddress)}

app/address/[address]/components/TransactionTable.tsx

@@ -22,7 +22,7 @@ export function TransactionTable({ address, data, currentPage, totalPages, pageS
       if (other === 'shielded') return <TxTypeBadge category="shielded" />;
       return other && other !== address ? <HashLink value={other} href={`/address/${other}`} lead={6} tail={4} copy={false} /> : <span className="text-xs text-muted">—</span>;
     } },
-    { id: 'block', header: 'Block', className: 'hidden md:table-cell', cell: tx => tx.blockHeight ? <Link href={`/block/${tx.blockHeight}`} className="text-xs font-mono text-secondary hover:text-primary">{tx.blockHeight.toLocaleString('en-US')}</Link> : <span className="text-xs text-muted">—</span> },
+    { id: 'block', header: 'Block', className: 'hidden md:table-cell', cell: tx => tx.blockHeight ? <Link href={`/block/${tx.blockHeight}`} prefetch={false} className="text-xs font-mono text-secondary hover:text-primary">{tx.blockHeight.toLocaleString('en-US')}</Link> : <span className="text-xs text-muted">—</span> },
     { id: 'amount', header: `Balance change (${CURRENCY})`, align: 'right', cell: tx => <span className={`text-xs font-mono whitespace-nowrap ${tx.amount === 0 ? 'text-secondary' : tx.type === 'received' ? 'text-cipher-green' : 'text-danger'}`}>{tx.amount === 0 ? '' : tx.type === 'received' ? '+' : '−'}{Math.abs(tx.amount).toLocaleString('en-US', { maximumFractionDigits: 8 })}</span> },
     { id: 'age', header: 'Age', align: 'right', cell: tx => <RelativeTime timestamp={tx.timestamp} className="text-xs text-muted whitespace-nowrap" /> },
   ];

app/address/[address]/components/UnifiedAddressViewer.tsx

@@ -23,7 +23,7 @@ export function UnifiedAddressViewer({ uaComponents, uaLoading, copiedText, onCo
         <div><TxTypeBadge category={receiver.key} /></div>
         <div className="min-w-0">
           {receiver.address ? <div className="flex items-start gap-2"><code className="min-w-0 break-all text-xs text-secondary">{receiver.address}</code><CopyButton text={receiver.address} label={receiver.key} copiedText={copiedText} onCopy={onCopy} /></div> : <p className="text-sm text-secondary">Receiver present · use the Unified Address</p>}
-          {receiver.key === 'transparent' && receiver.address ? <Link className="inline-flex mt-3 rounded border border-cipher-border px-3 py-2 text-xs font-mono text-primary hover:bg-cipher-hover" href={`/address/${receiver.address}`}>View transparent activity →</Link> : <p className="text-xs text-muted mt-2">Balance and history remain private.</p>}
+          {receiver.key === 'transparent' && receiver.address ? <Link className="inline-flex mt-3 rounded border border-cipher-border px-3 py-2 text-xs font-mono text-primary hover:bg-cipher-hover" href={`/address/${receiver.address}`} prefetch={false}>View transparent activity →</Link> : <p className="text-xs text-muted mt-2">Balance and history remain private.</p>}
         </div>
       </div>)}
       {!receivers.length && <p className="p-5 text-sm text-muted">No supported receiver details were returned by the decoder.</p>}

app/api/governance/announcement/route.ts

@@ -1,11 +1,13 @@
 import { getGovernanceCatalog } from '@/lib/governance-data';
-import { selectAnnouncement } from '@/lib/governance';
+import { announcementCacheHeaders, buildAnnouncementSnapshot } from '@/lib/governance-announcement';
 import { getNetwork } from '@/lib/seo';
 
 export async function GET() {
-  if (getNetwork() !== 'mainnet') return Response.json({ announcement: null }, { headers: { 'X-Robots-Tag': 'noindex' } });
+  if (getNetwork() !== 'mainnet') return Response.json(
+    { announcement: null, generatedAt: Date.now(), nextChangeAt: null },
+    { headers: announcementCacheHeaders(60) },
+  );
   const catalog = await getGovernanceCatalog();
-  return Response.json({ announcement: selectAnnouncement(catalog, Date.now()) }, { headers: {
-    'Cache-Control': 'no-store', 'X-Robots-Tag': 'noindex',
-  } });
+  const { snapshot, ttl } = buildAnnouncementSnapshot(catalog, Date.now());
+  return Response.json(snapshot, { headers: announcementCacheHeaders(ttl) });
 }

app/block/[height]/FutureBlockView.tsx

@@ -48,7 +48,7 @@ export function FutureBlockView({
             )}
             <div className="flex flex-wrap items-center justify-center gap-3">
               <Link
-                href={`/block/${targetHeight}`}
+                href={`/block/${targetHeight}`} prefetch={false}
                 className="btn btn-md btn-primary"
               >
                 View Block →
@@ -134,7 +134,7 @@ export function FutureBlockView({
           <dl className="mt-6 grid grid-cols-1 gap-5 border-t border-cipher-border pt-6 sm:grid-cols-2 sm:gap-8">
             <div>
               <dt className="text-sm text-secondary mb-2">Latest block</dt>
-              <dd className="font-mono text-primary tabular-nums"><Link href={`/block/${currentHeight}`} className="hover:text-cipher-gold transition-colors">#{currentHeight.toLocaleString('en-US')}</Link></dd>
+              <dd className="font-mono text-primary tabular-nums"><Link href={`/block/${currentHeight}`} prefetch={false} className="hover:text-cipher-gold transition-colors">#{currentHeight.toLocaleString('en-US')}</Link></dd>
             </div>
             <div>
               <dt className="text-sm text-secondary mb-2">{upgrade ? 'Activation block' : 'Upcoming block'}</dt>

app/block/[height]/components/BlockPageHeader.tsx

@@ -16,7 +16,7 @@
   const disabled = !hash;
   return (
     <Link
-      href={disabled ? '#' : `/block/${height}`}
+      href={disabled ? '#' : `/block/${height}`} prefetch={false}
       aria-disabled={disabled}
       className={`inline-flex items-center gap-1.5 px-3 py-1.5 rounded-md border text-xs font-mono transition-colors ${
         disabled
@@ -102,12 +102,12 @@
                 solution: data.solution,
                 totalFees: data.totalFees,
                 minerAddress: data.minerAddress,
                 transactions: data.transactions?.map((tx: any) => ({
                   txid: tx.txid,
                   type: tx.vin?.[0]?.coinbase ? 'coinbase' : tx.hasShieldedActivity ? 'shielded' : 'regular',
                   inputs: tx.vin?.length || 0,
                   outputs: tx.vout?.length || 0,
                   amount: tx.vout?.reduce((sum: number, out: any) => sum + (out.value || 0), 0) || 0
                 }))
               }}
               csvData={data.transactions}
@@ -115,12 +115,12 @@
               type="both"
               label="Export"
               csvHeaders={['TXID', 'Type', 'Inputs', 'Outputs', 'Amount (ZEC)']}
               csvMapper={(tx: any) => [
                 tx.txid,
                 tx.vin?.[0]?.coinbase ? 'Coinbase' : tx.hasShieldedActivity ? 'Shielded' : 'Regular',
                 String(tx.vin?.length || 0),
                 String(tx.vout?.length || 0),
                 tx.vout?.reduce((sum: number, out: any) => sum + (out.value || 0), 0).toFixed(8) || '0'
               ]}
             />
           </div>

app/block/[height]/components/BlockPageSkeleton.tsx

@@ -1,3 +1,4 @@
+import Link from 'next/link';
 import { SkeletonTable } from '@/components/ui/EmptyState';
 import { Skeleton } from '@/components/ui/Skeleton';
 import { Card, CardHeader, CardBody } from '@/components/ui/Card';
@@ -50,6 +51,14 @@ export function BlockPageSkeleton({
             </>
           )}
         </p>
+        {initialSummary?.isOrphaned && initialSummary.canonicalReplacementHeight != null && (
+          <p className="mt-2 text-xs sm:text-sm text-secondary">
+            Canonical replacement at this height:{' '}
+            <Link href={`/block/${initialSummary.canonicalReplacementHeight}`} prefetch={false} className="text-brand-gold hover:underline">
+              Zcash block #{initialSummary.canonicalReplacementHeight.toLocaleString('en-US')}
+            </Link>.
+          </p>
+        )}
         {/* Server-seeded facts from the SEO resolution fetch — real content
             instead of a shimmer while the full block detail loads client-side. */}
         {initialSummary && (initialSummary.timestamp != null || initialSummary.transactionCount != null || initialSummary.size != null) && (

app/block/[height]/components/types.ts

@@ -60,6 +60,8 @@ export interface BlockPageSummary {
   hash: string;
   firstSeenAt?: string | null;
   isOrphaned: boolean;
+  /** Present only when the API identifies a different canonical block at this height. */
+  canonicalReplacementHeight?: number | null;
   /**
    * Extra fields already available from the server-side block resolution
    * (`getBlockResolution` in lib/seo.ts) used for SEO metadata. Threading

app/block/[height]/page.tsx

@@ -5,6 +5,7 @@ import {
   getApiUrl,
   getNetwork,
   getBlockResolution,
+  BLOCK_HASH_PATTERN,
   normalizeBlockIdentifier,
   type BlockRecord,
 } from '@/lib/seo';
@@ -92,6 +93,10 @@ export default async function BlockPage({
   const height = Number(block.height);
   const hash = block.hash.toLowerCase();
   const isOrphaned = block.isOrphaned === true;
+  const replacementHash = block.canonicalBlock?.hash;
+  const canonicalReplacementHeight = isOrphaned && typeof replacementHash === 'string'
+    && BLOCK_HASH_PATTERN.test(replacementHash) && replacementHash.toLowerCase() !== hash
+    ? height : null;
   const rawTransactionCount = block.transactionCount ?? block.transaction_count ?? null;
   const transactionCount = rawTransactionCount === null || rawTransactionCount === undefined
     ? null
@@ -104,6 +109,7 @@ export default async function BlockPage({
     height,
     hash,
     isOrphaned,
+    canonicalReplacementHeight,
     timestamp: Number.isFinite(timestamp) ? timestamp : null,
     transactionCount: Number.isFinite(transactionCount) ? transactionCount : null,
     size: Number.isFinite(size) ? size : null,

app/blocks/BlocksClient.tsx

@@ -112,7 +112,7 @@ function blockColumns(blocks: Block[], trailingBlock: Block | null, schedule: Bl
       skeletonWidth: 'w-24',
       cell: (block) => (
         <div className="flex items-center gap-2">
-          <Link href={`/block/${block.height}`} className="font-mono text-sm text-primary hover:text-primary transition-colors">
+          <Link href={`/block/${block.height}`} prefetch={false} className="font-mono text-sm text-primary hover:text-primary transition-colors">
             {block.height.toLocaleString()}
           </Link>
           {block.finality_status === 'Finalized' && (

app/finalizer/[pubkey]/page.tsx

@@ -384,7 +384,7 @@ export default function FinalizerPage() {
                         <StakingActionBadge type={a.action_type} compact />
                       </td>
                       <td className="px-3 sm:px-4 py-3">
-                        <Link href={`/block/${a.block_height}`} className="text-cipher-gold hover:underline font-mono">
+                        <Link href={`/block/${a.block_height}`} prefetch={false} className="text-cipher-gold hover:underline font-mono">
                           #{a.block_height.toLocaleString()}
                         </Link>
                       </td>
@@ -609,6 +609,7 @@ function DelegatorsPanel({ actions }: { actions: StakeAction[] }) {
                     <td className="px-3 sm:px-4 py-3">
                       <Link
                         href={`/block/${d.lastActionHeight}`}
+                        prefetch={false}
                         className="text-cipher-gold hover:underline font-mono"
                       >
                         #{d.lastActionHeight.toLocaleString()}

app/governance/HowToVote.tsx

@@ -27,7 +27,7 @@ export function HowToVote({ snapshotHeight }: { snapshotHeight?: number }) {
           <h3 className="text-sm font-medium text-primary"><span className="mr-2 font-mono text-cipher-gold">02</span>Check your eligible balance</h3>
           <p className="mt-2 text-sm leading-relaxed text-secondary">Follow the wallet’s eligibility check. Each poll uses a snapshot: an earlier point in the blockchain used to determine which funds can vote.</p>
           {snapshotHeight !== undefined && (
-            <Link href={`/block/${snapshotHeight}`} className="mt-2 inline-block text-xs text-cipher-gold hover:underline">
+            <Link href={`/block/${snapshotHeight}`} prefetch={false} className="mt-2 inline-block text-xs text-cipher-gold hover:underline">
               This poll’s snapshot: block {snapshotHeight.toLocaleString('en-US')} →
             </Link>
           )}

app/governance/nu7/NU7VoteClient.tsx

@@ -275,7 +275,7 @@ export function NU7VoteClient({ initialData, resultsState, resultsContent, initi
             {countdownLabel}
           </span>
           {phase === 'pre-snapshot' && (
-            <Link href={`/block/${NU7_VOTE.snapshotHeight}`} className="text-caption font-mono text-muted hover:text-primary transition-colors ml-auto">
+            <Link href={`/block/${NU7_VOTE.snapshotHeight}`} prefetch={false} className="text-caption font-mono text-muted hover:text-primary transition-colors ml-auto">
               Block #{NU7_VOTE.snapshotHeight.toLocaleString()}
             </Link>
           )}

app/name/[name]/NameClient.tsx

@@ -106,7 +106,7 @@ function RegisteredView({
           <Field label="Resolves to">
             <div className="flex items-center">
               <Link
-                href={`/address/${registration.address}`}
+                href={`/address/${registration.address}`} prefetch={false}
                 className="font-mono text-sm hover:text-primary transition-colors break-all"
               >
                 {registration.address}
@@ -128,7 +128,7 @@ function RegisteredView({
           <Field label="Block">
             <div className="flex items-center">
               <Link
-                href={`/block/${registration.height}`}
+                href={`/block/${registration.height}`} prefetch={false}
                 className="font-mono text-sm hover:text-primary transition-colors"
               >
                 {registration.height.toLocaleString('en-US')}
@@ -191,7 +191,7 @@ function RegisteredView({
                       </td>
                       <td className="py-2 pr-4 font-mono">
                         <Link
-                          href={`/block/${e.height}`}
+                          href={`/block/${e.height}`} prefetch={false}
                           className="hover:text-primary transition-colors"
                         >
                           {e.height.toLocaleString('en-US')}

app/network/NetworkClient.tsx

@@ -156,7 +156,7 @@ export default function NetworkClient({ initialData }: { initialData: NetworkPag
           </dl>
           <dl id="network-overview" className="network-section network-summary-grid network-live-facts" aria-label="Current chain activity">
             {[
-              { label: 'Latest block', value: height != null ? <Link href={`/block/${height}`} className="hover:text-cipher-gold">{height.toLocaleString()}</Link> : '—', hint: stats ? `Block timestamp · ${blockAgeLabel(stats.blockchain.latestBlockTime, now)}` : 'Awaiting chain data' },
+              { label: 'Latest block', value: height != null ? <Link href={`/block/${height}`} prefetch={false} className="hover:text-cipher-gold">{height.toLocaleString()}</Link> : '—', hint: stats ? `Block timestamp · ${blockAgeLabel(stats.blockchain.latestBlockTime, now)}` : 'Awaiting chain data' },
               { label: 'Average block interval', value: stats?.mining.avgBlockTime != null ? `${stats.mining.avgBlockTime.toFixed(1)}s` : '—', hint: stats?.mining.targetBlockTime != null ? `Observed · protocol target ${stats.mining.targetBlockTime}s` : 'Observed · protocol target unavailable' },
               { label: 'Transactions · 24h', value: txCount?.toLocaleString() ?? '—', hint: stats?.blockchain.tx24hExclCoinbase != null ? 'Confirmed · coinbase excluded' : 'Confirmed · includes coinbase' },
               { label: 'Estimated hashrate · 24h', value: stats?.mining.hashrateEstimate ? stats.mining.networkHashrate : '—', hint: <Link href="/mining#metrics" className="hover:text-primary underline underline-offset-4">Trailing 24-hour estimate →</Link> },

app/network/page.tsx

@@ -70,7 +70,7 @@ export default async function NetworkPage() {
     <section className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 pb-12">
       <div className="border-t border-cipher-border pt-6 max-w-3xl text-sm text-muted space-y-2">
         <h2 className="font-mono font-medium text-secondary">About these observations</h2>
-        {nu7Height != null && <p>The serving node announces NU7 at <Link href={`/block/${nu7Height}`} className="text-brand-gold hover:underline">block #{nu7Height.toLocaleString('en-US')}</Link> on Zcash {network}. {nu7Active ? <>The upgrade is active; explore <Link href="#nu7-accounting" className="text-brand-gold hover:underline">fee allocation and NSM accounting</Link> below.</> : <>View its canonical block or the estimated activation countdown.</>}</p>}
+        {nu7Height != null && <p>The serving node announces NU7 at <Link href={`/block/${nu7Height}`} prefetch={false} className="text-brand-gold hover:underline">block #{nu7Height.toLocaleString('en-US')}</Link> on Zcash {network}. {nu7Active ? <>The upgrade is active; explore <Link href="#nu7-accounting" className="text-brand-gold hover:underline">fee allocation and NSM accounting</Link> below.</> : <>View its canonical block or the estimated activation countdown.</>}</p>}
         <p>Chain statistics, recent blocks and node discovery are separate observations and can update at different times. Block cadence uses timestamps recorded in blocks; these are not measurements of when this explorer received them.</p>
         <p>The map shows observed reachable nodes, not a census of every Zcash node. Peer connections and disk usage in Technical details describe this explorer’s node. Observed transaction fees describe past transactions and are not fee recommendations.</p>
       </div>