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/mongodb/connection.ts

@@ -0,0 +1,82 @@
+/**
+ * Conexão MongoDB usando Mongoose
+ * Singleton pattern para reutilizar conexão
+ */
+
+import mongoose from "mongoose";
+
+function getMongoUrl(): string {
+  const url = process.env.MONGO_URL;
+  if (!url) {
+    throw new Error("MONGO_URL não está definida nas variáveis de ambiente");
+  }
+  return url;
+}
+
+interface MongooseCache {
+  conn: typeof mongoose | null;
+  promise: Promise<typeof mongoose> | null;
+}
+
+// Cache global para Next.js (evita múltiplas conexões em hot reload)
+declare global {
+  // eslint-disable-next-line no-var
+  var mongoose: MongooseCache | undefined;
+}
+
+let cached: MongooseCache = global.mongoose || { conn: null, promise: null };
+
+if (!global.mongoose) {
+  global.mongoose = cached;
+}
+
+/**
+ * Conecta ao MongoDB ou retorna conexão existente
+ */
+export async function connectMongoDB(): Promise<typeof mongoose> {
+  if (cached.conn) {
+    return cached.conn;
+  }
+
+  if (!cached.promise) {
+    const opts = {
+      bufferCommands: false,
+      maxPoolSize: 10,
+      serverSelectionTimeoutMS: 5000,
+      socketTimeoutMS: 45000,
+    };
+
+    cached.promise = mongoose
+      .connect(getMongoUrl(), opts)
+      .then((mongoose) => {
+        // Conexão MongoDB estabelecida (log desabilitado)
+        return mongoose;
+      })
+      .catch((error) => {
+        console.error("❌ Erro ao conectar MongoDB:", error);
+        cached.promise = null;
+        throw error;
+      });
+  }
+
+  try {
+    cached.conn = await cached.promise;
+  } catch (e) {
+    cached.promise = null;
+    throw e;
+  }
+
+  return cached.conn;
+}
+
+/**
+ * Desconecta do MongoDB (útil para testes)
+ */
+export async function disconnectMongoDB(): Promise<void> {
+  if (cached.conn) {
+    await mongoose.disconnect();
+    cached.conn = null;
+    cached.promise = null;
+  }
+}
+