feat(marketplace): buyer escrow refund after locktime

Completes the escrow safety loop: a buyer whose escrow token is past its
locktime can reclaim it from the listing card ('Refund escrow'), which redeems
the P2PK token with their refund key. Native-only, same as the rest of escrow.

src/components/MarketplaceItemCard.tsx

@@ -35,6 +35,7 @@ import { useMarkListingSold } from '@/hooks/useMarkListingSold';
 import { MarkSoldDialog } from '@/components/MarkSoldDialog';
 import { EscrowRequestDialog } from '@/components/EscrowRequestDialog';
 import { useCashuEscrow } from '@/hooks/wallet/useCashuEscrow';
+import { parseEscrowToken } from '@/lib/cashuEscrow';
 import { useListingTrade, useTradeAttestation, useTradeReputation, useListingTradeRequest, useTradeAttestationRequest } from '@/hooks/useTradeAttestations';
 import { DeleteEntityDialog } from '@/components/DeleteEntityDialog';
 import { genUserName } from '@/lib/genUserName';
@@ -224,6 +225,38 @@ export function MarketplaceItemCard({ item, compact = false }: MarketplaceItemCa
     !sellerNamedMe &&
     !iRequestedConfirmation;
 
+  // The buyer's own escrow token (from their published 31872), refundable after
+  // the locktime if the seller never delivered.
+  const myEscrowToken = requestState?.requests
+    .find((e) => e.pubkey === user?.pubkey)
+    ?.tags.find(([t]) => t === 'cashu_token')?.[1];
+  const myEscrowRefundable = (() => {
+    if (!myEscrowToken) return false;
+    try {
+      const info = parseEscrowToken(myEscrowToken);
+      return info.locked && info.refundable;
+    } catch {
+      return false;
+    }
+  })();
+
+  const handleRefundEscrow = async () => {
+    if (!myEscrowToken) return;
+    try {
+      await escrow.redeemEscrow(myEscrowToken);
+      toast({
+        title: 'Escrow refunded',
+        description: 'The funds are back in your Cashu wallet.',
+      });
+    } catch (e) {
+      toast({
+        title: 'Could not refund escrow',
+        description: e instanceof Error ? e.message : 'Something went wrong.',
+        variant: 'destructive',
+      });
+    }
+  };
+
   const handleConfirmTrade = async () => {
     if (!user) return;
     try {
@@ -576,6 +609,19 @@ export function MarketplaceItemCard({ item, compact = false }: MarketplaceItemCa
                 </p>
               )}
 
+              {/* Buyer: reclaim escrow after the locktime if the seller didn't deliver */}
+              {escrow.available && myEscrowRefundable && (
+                <Button
+                  size="sm"
+                  variant="outline"
+                  onClick={handleRefundEscrow}
+                  className="w-full gap-2 border-[#ccff00]/40 text-[#ccff00] hover:bg-[#ccff00]/10"
+                >
+                  <RotateCcw className="h-4 w-4" />
+                  Refund escrow
+                </Button>
+              )}
+
               {/* Contact button */}
               <Button
                 variant="outline"