feat: enhance purchase intentions with chat integration and offer tracking

- Added MongoDB chat/message integration for seller responses
- Improved seller response validation and default messaging
- Integrated automatic chat creation/update when responding to intentions
- Added highest custom offer fields to listing queries and models
- Enhanced listing data with top offer information for buyers

components/marketplace/MyAdsIntentionList.tsx

@@ -16,6 +16,9 @@ interface PurchaseIntention {
   buyer_message: string | null;
   seller_response: string | null;
   created_at: string;
+  custom_offer_amount: number | null;
+  custom_offer_currency: string | null;
+  custom_offer_created_at: string | null;
   buyer?: {
     user_id: number;
     username: string;
@@ -82,6 +85,28 @@ function getPaymentMethodLabel(method: string): string {
   }
 }
 
+function formatCustomOffer(intention: PurchaseIntention): string | null {
+  if (
+    intention.custom_offer_amount === null ||
+    intention.custom_offer_amount === undefined ||
+    !intention.custom_offer_currency
+  ) {
+    return null;
+  }
+
+  const amount = intention.custom_offer_amount;
+  switch (intention.custom_offer_currency) {
+    case "pix":
+      return `R$ ${amount.toFixed(2)}`;
+    case "tibia_coins":
+      return `${Math.round(amount).toLocaleString("pt-BR")} TC`;
+    case "gold_coins":
+      return `${Math.round(amount).toLocaleString("pt-BR")} GP`;
+    default:
+      return amount.toLocaleString("pt-BR");
+  }
+}
+
 export function MyAdsIntentionList({ listingId, sellerId }: MyAdsIntentionListProps) {
   const [intentions, setIntentions] = useState<PurchaseIntention[]>([]);
   const [loading, setLoading] = useState(true);
@@ -196,6 +221,18 @@ export function MyAdsIntentionList({ listingId, sellerId }: MyAdsIntentionListPr
                     <Clock className="h-3 w-3" />
                     <span>{formatTimeAgo(new Date(intention.created_at))}</span>
                   </div>
+                  {formatCustomOffer(intention) && (
+                    <div className="flex items-center gap-2 mb-1">
+                      <Badge variant="outline" className="border-primary text-primary">
+                        Oferta: {formatCustomOffer(intention)}
+                      </Badge>
+                      {intention.custom_offer_created_at && (
+                        <span className="text-[10px] text-muted-foreground">
+                          {new Date(intention.custom_offer_created_at).toLocaleString("pt-BR")}
+                        </span>
+                      )}
+                    </div>
+                  )}
                   {intention.buyer_message && (
                     <p className="text-xs text-muted-foreground line-clamp-1">
                       <MessageSquare className="h-3 w-3 inline mr-1" />