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/characters.ts

@@ -69,6 +69,21 @@ export async function getUserCharacters(userId: number): Promise<Character[]> {
   });
 }
 
+/**
+ * Busca personagem principal de um usuário
+ */
+export async function getMainCharacter(userId: number): Promise<Character | null> {
+  return await prisma.userCharacter.findFirst({
+    where: {
+      user_id: userId,
+      is_main: true,
+    },
+    orderBy: [
+      { created_at: "asc" },
+    ],
+  });
+}
+
 /**
  * Busca personagem principal de um usuário em um servidor específico
  */