feat(market): add Minha Intenções tab with panel, hook, and badge

- Introduced "Minhas Intenções" tab visible only to logged-in users.
- Integrated MyPurchaseIntentionsPanel and useMyPurchaseIntentions hook.
- Added tab badge showing count of pending intentions.
- Extended session API to include user’s main character for downstream features.

lib/prisma/queries/purchase-intentions.ts

@@ -20,6 +20,7 @@ export interface PurchaseIntention {
   listing_id: number;
   buyer_id: number;
   payment_method: string;
+  payment_method_change_count: number;
   status: PurchaseIntentionStatus;
   buyer_message: string | null;
   seller_response: string | null;
@@ -251,3 +252,123 @@ export async function hasPendingIntention(
   return count > 0;
 }
 
+/**
+ * Busca intenção pendente de um comprador para um listing específico
+ */
+export async function getPendingIntentionByBuyerAndListing(
+  listingId: number,
+  buyerId: number
+): Promise<PurchaseIntention | null> {
+  return await prisma.purchaseIntention.findFirst({
+    where: {
+      listing_id: listingId,
+      buyer_id: buyerId,
+      status: "pending",
+    },
+    include: {
+      listing: {
+        select: {
+          listing_id: true,
+          item_name: true,
+          seller_id: true,
+        },
+      },
+      buyer: {
+        select: {
+          user_id: true,
+          username: true,
+          email: true,
+        },
+      },
+    },
+    orderBy: {
+      created_at: "desc",
+    },
+  }) as PurchaseIntention | null;
+}
+
+/**
+ * Atualiza o método de pagamento de uma intenção
+ */
+export async function updatePurchaseIntentionPaymentMethod(
+  intentionId: number,
+  newPaymentMethod: PaymentMethod
+): Promise<PurchaseIntention> {
+  // Buscar intenção atual
+  const intention = await prisma.purchaseIntention.findUnique({
+    where: { intention_id: intentionId },
+  });
+
+  if (!intention) {
+    throw new Error("Intenção não encontrada");
+  }
+
+  // Verificar se pode trocar (máximo 1 troca)
+  if (intention.payment_method_change_count >= 1) {
+    throw new Error("Você já atingiu o limite de trocas de método de pagamento");
+  }
+
+  // Verificar se o novo método é diferente
+  if (intention.payment_method === newPaymentMethod) {
+    throw new Error("O novo método de pagamento deve ser diferente do atual");
+  }
+
+  // Atualizar
+  return await prisma.purchaseIntention.update({
+    where: { intention_id: intentionId },
+    data: {
+      payment_method: newPaymentMethod,
+      payment_method_change_count: intention.payment_method_change_count + 1,
+      updated_at: new Date(),
+    },
+    include: {
+      listing: {
+        select: {
+          listing_id: true,
+          item_name: true,
+          seller_id: true,
+        },
+      },
+      buyer: {
+        select: {
+          user_id: true,
+          username: true,
+          email: true,
+        },
+      },
+    },
+  }) as PurchaseIntention;
+}
+
+/**
+ * Retorna os IDs de anúncios com intenções pendentes para um comprador
+ */
+export async function getPendingIntentionListingIdsForBuyer(
+  buyerId: number,
+  listingIds: number[]
+): Promise<number[]> {
+  if (listingIds.length === 0) {
+    return [];
+  }
+
+  const intentions = await prisma.purchaseIntention.findMany({
+    where: {
+      buyer_id: buyerId,
+      status: "pending",
+      listing_id: {
+        in: listingIds,
+      },
+    },
+    select: {
+      listing_id: true,
+    },
+  });
+
+  const uniqueIds = new Set<number>();
+  intentions.forEach((intention) => {
+    uniqueIds.add(intention.listing_id);
+  });
+
+  return Array.from(uniqueIds);
+}
+