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

lib/prisma/queries/items.ts

@@ -1,4 +1,4 @@
-/**
+/**
  * Queries de itens usando Prisma
  * Busca itens da tabela unificada items (PostgreSQL)
  */