fix(escrow): show and choose the mint, block non-P2PK mints

The escrow mint was silently the buyer's preferred/first trusted mint
(useCashuEscrow: prefs.preferredMintUrl || mints[0].url) with no UI, even
though the seller redeems there. Now:
- the escrow dialog shows the mint and lets the buyer pick from their
  trusted mints (defaults to their preference);
- a mint whose NUT-06 info advertises no NUT-11 (P2PK) support is blocked
  with a clear message before minting (cashuEscrow.mintSupportsP2PK);
- the create call uses the selected mint.
Still open (scoped separately): consult a seller-advertised mint and
seller-side receive from an unfamiliar mint. Recorded in the audit.

MARKETPLACE_FLOW_AUDIT.md

@@ -65,6 +65,16 @@ visibility, terminology, translation).
   runs `markSold` then `publishTrade` non-atomically; if the second fails (or is
   queued offline, which resolves — `useNostrPublish.ts:77-89`), the listing is
   sold but no `31871` exists, so no reputation and no confirmation path.
+- **[verified] Escrow mint is chosen by the buyer, not the payee.**
+  `useCashuEscrow` resolves the mint as `prefs.preferredMintUrl || mints[0].url`
+  (the buyer's first trusted mint, `useCashuEscrow.ts:40,103`), and
+  `EscrowRequestDialog` did not show or offer a choice. The token is P2PK-locked
+  to the seller but lives at the buyer's mint, so a seller who does not
+  trust/reach that mint may fail to redeem. There was also no P2PK (NUT-11)
+  capability check before minting (`cashuEscrow.ts:261-282`). **Partly fixed this
+  pass**: the buyer now sees and picks the mint in the dialog, and a mint that
+  advertises no NUT-11 is blocked with a clear message. Still open: consult a
+  seller-advertised mint, and seller-side receive from an unfamiliar mint.
 
 ---
 
@@ -190,6 +200,10 @@ Second batch (payment, attestation, escrow):
    (`lib/pendingEscrow.ts`) *before* publishing the request, so a failed send
    cannot strand the locked funds, and the failure message says so. (Still a
    mitigation: there is no re-send/recover UI yet.)
+10. **Escrow mint selection:** the escrow dialog now shows the mint and lets the
+    buyer pick from their trusted mints; a mint whose NUT-06 info advertises no
+    NUT-11 (P2PK) support is blocked with a clear message
+    (`cashuEscrow.mintSupportsP2PK`), instead of failing deep in minting.
 
 ## 7. Recommended order
 

src/components/EscrowRequestDialog.tsx

@@ -13,7 +13,7 @@ import { useCashuEscrow } from '@/hooks/wallet/useCashuEscrow';
 import { useEscrowPrefs } from '@/hooks/wallet/useEscrowPrefs';
 import { useTradeAttestationRequest } from '@/hooks/useTradeAttestations';
 import { useToast } from '@/hooks/useToast';
-import { ESCROW_MIN_LOCK_DAYS } from '@/lib/cashuEscrow';
+import { ESCROW_MIN_LOCK_DAYS, mintSupportsP2PK } from '@/lib/cashuEscrow';
 import { savePendingEscrow, clearPendingEscrow } from '@/lib/pendingEscrow';
 import { Loader2, Lock } from 'lucide-react';
 import { useTranslation } from '@/contexts/language';
@@ -48,6 +48,13 @@ export function EscrowRequestDialog({
   const [amount, setAmount] = useState('');
   const [days, setDays] = useState(String(prefs.defaultLockDays));
   const [busy, setBusy] = useState(false);
+  // Buyer-facing mint choice: default to their preference, else the first trusted
+  // mint. Shown explicitly so the buyer knows where the funds will be locked.
+  const [mintChoice, setMintChoice] = useState('');
+  const mintOptions = escrow.mints;
+  const effectiveMint = mintChoice || prefs.preferredMintUrl || mintOptions[0]?.url || '';
+  const p2pkBlocked =
+    mintSupportsP2PK(mintOptions.find((m) => m.url === effectiveMint)?.info) === false;
 
   const submit = async () => {
     const amountSats = parseInt(amount, 10);
@@ -65,7 +72,7 @@ export function EscrowRequestDialog({
     setBusy(true);
     let mintedToken: string | undefined;
     try {
-      const { token } = await escrow.createEscrow({ amountSats, sellerPubkey, lockDays, mintUrl: prefs.preferredMintUrl || undefined });
+      const { token } = await escrow.createEscrow({ amountSats, sellerPubkey, lockDays, mintUrl: effectiveMint || undefined });
       mintedToken = token;
       // Persist BEFORE publishing: if the request fails to send, the P2PK-locked
       // funds stay recoverable from this device instead of being lost.
@@ -124,6 +131,28 @@ export function EscrowRequestDialog({
             />
           </div>
 
+          <div className="space-y-2">
+            <Label htmlFor="escrow-mint" className="text-xs uppercase tracking-wide text-gray-400">
+              {t('marketUi.escrowRequest.mintLabel')}
+            </Label>
+            <select
+              id="escrow-mint"
+              value={effectiveMint}
+              onChange={(e) => setMintChoice(e.target.value)}
+              className="h-11 w-full rounded-md border border-gray-700 bg-gray-900 px-3 text-sm text-white"
+            >
+              {mintOptions.length === 0 && (
+                <option value="">{t('marketUi.escrowRequest.noMints')}</option>
+              )}
+              {mintOptions.map((m) => (
+                <option key={m.url} value={m.url}>
+                  {m.url.replace(/^https?:\/\//, '')}
+                </option>
+              ))}
+            </select>
+            <p className="text-[11px] text-gray-500">{t('marketUi.escrowRequest.mintHint')}</p>
+          </div>
+
           <div className="space-y-2">
             <Label htmlFor="escrow-days" className="text-xs uppercase tracking-wide text-gray-400">
               {t('marketUi.escrowRequest.daysLabel')}
@@ -145,6 +174,9 @@ export function EscrowRequestDialog({
               {t('marketUi.escrowRequest.nativeOnly')}
             </p>
           )}
+          {p2pkBlocked && (
+            <p className="text-xs text-amber-400">{t('marketUi.escrowRequest.p2pkUnsupported')}</p>
+          )}
 
           <div className="flex gap-2 pt-1">
             <Button variant="outline" onClick={() => onOpenChange(false)} className="flex-1 border-white/15">
@@ -152,7 +184,7 @@ export function EscrowRequestDialog({
             </Button>
             <Button
               onClick={submit}
-              disabled={pending || !escrow.available}
+              disabled={pending || !escrow.available || p2pkBlocked}
               className="flex-1 gap-2 bg-[#ff6600] font-bold text-black hover:bg-[#ff6600]/90"
             >
               {pending ? <Loader2 className="h-4 w-4 animate-spin" /> : <Lock className="h-4 w-4" />}

src/hooks/wallet/useCashuEscrow.ts

@@ -148,6 +148,8 @@ export function useCashuEscrow() {
   return {
     available,
     defaultMintUrl,
+    /** The buyer's trusted mints, for the escrow mint picker. */
+    mints,
     getEscrowPubkey,
     createEscrow,
     redeemEscrow,

src/i18n/en.ts

@@ -2079,6 +2079,10 @@ marketUi: {
       daysLabel: 'Buyer refund after (days)',
       daysHint: "After this many days you can reclaim the funds if the seller hasn't delivered.",
       lockedNotSent: 'Funds are locked in escrow and saved on this device, but the request did not send. Reopen the listing to retry. Do not pay again.',
+      mintLabel: 'Mint (where the funds are locked)',
+      mintHint: 'Escrow lives at this mint. The seller redeems here, so pick one you both trust.',
+      noMints: 'No mints available',
+      p2pkUnsupported: 'This mint does not advertise P2PK (NUT-11) support, so escrow cannot be locked here. Choose another mint.',
       nativeOnly: 'Cashu escrow is available in the SkateSpots app only (not the web build).',
       lockAndRequest: 'Lock & request',
     },

src/i18n/es.ts

@@ -2079,6 +2079,10 @@ marketUi: {
       daysLabel: 'Reembolso del comprador tras (días)',
       daysHint: 'Tras estos días puedes recuperar los fondos si el vendedor no ha entregado.',
       lockedNotSent: 'Los fondos están bloqueados en escrow y guardados en este dispositivo, pero la solicitud no se envió. Reabre el anuncio para reintentar. No pagues otra vez.',
+      mintLabel: 'Mint (donde se bloquean los fondos)',
+      mintHint: 'El escrow vive en este mint. El vendedor lo canjea aquí, así que elige uno en el que confiéis ambos.',
+      noMints: 'No hay mints disponibles',
+      p2pkUnsupported: 'Este mint no anuncia compatibilidad con P2PK (NUT-11), así que el escrow no se puede bloquear aquí. Elige otro mint.',
       nativeOnly: 'El depósito en garantía Cashu solo está disponible en la app de SkateSpots (no en la versión web).',
       lockAndRequest: 'Bloquear y solicitar',
     },

src/lib/cashuEscrow.ts

@@ -216,6 +216,18 @@ export interface EscrowMintWallet {
 
 export const MINT_QUOTE_PAID = 'PAID';
 
+/**
+ * Whether a mint's NUT-06 info advertises NUT-11 (P2PK) support. Returns
+ * `undefined` when the info is unknown, so callers can proceed optimistically
+ * rather than block on missing metadata.
+ */
+export function mintSupportsP2PK(info: unknown): boolean | undefined {
+  if (!info || typeof info !== 'object') return undefined;
+  const nuts = (info as { nuts?: unknown }).nuts;
+  if (!nuts || typeof nuts !== 'object') return undefined;
+  return Object.prototype.hasOwnProperty.call(nuts, '11');
+}
+
 export interface CreateEscrowDeps {
   /** A cashu-ts Wallet (or compatible fake in tests) for the chosen mint. */
   wallet: EscrowMintWallet;