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.

app/api/chats/unread-count/route.ts

@@ -0,0 +1,70 @@
+/**
+ * GET /api/chats/unread-count
+ * Retorna contagem de usuários únicos com mensagens não vistas
+ */
+import { NextRequest, NextResponse } from "next/server";
+import { requireAuth } from "@/lib/auth/middleware";
+import { connectMongoDB } from "@/lib/mongodb/connection";
+import { Chat } from "@/lib/mongodb/models/Chat";
+import { secureLogger } from "@/lib/secure-logger";
+
+export async function GET(request: NextRequest) {
+  try {
+    const authResult = await requireAuth(request);
+    if (authResult instanceof NextResponse) return authResult;
+    const auth = authResult;
+
+    await connectMongoDB();
+
+    // Buscar todos os chats do usuário
+    const chats = await Chat.find({
+      $or: [{ buyer_id: auth.userId }, { seller_id: auth.userId }],
+      is_active: true,
+    });
+
+    // Calcular contagem de usuários únicos com mensagens não vistas
+    const uniqueUsersWithUnread = new Set<number>();
+
+    chats.forEach((chat) => {
+      let unreadCount = 0;
+      let otherUserId: number;
+
+      if (chat.buyer_id === auth.userId) {
+        unreadCount = chat.buyer_unread_count;
+        otherUserId = chat.seller_id;
+      } else {
+        unreadCount = chat.seller_unread_count;
+        otherUserId = chat.buyer_id;
+      }
+
+      // Se há mensagens não vistas, adicionar o outro usuário ao Set
+      if (unreadCount > 0) {
+        uniqueUsersWithUnread.add(otherUserId);
+      }
+    });
+
+    return NextResponse.json(
+      {
+        success: true,
+        count: uniqueUsersWithUnread.size,
+        totalUnreadMessages: chats.reduce((total, chat) => {
+          if (chat.buyer_id === auth.userId) {
+            return total + chat.buyer_unread_count;
+          }
+          return total + chat.seller_unread_count;
+        }, 0),
+      },
+      { status: 200 }
+    );
+  } catch (error) {
+    secureLogger.error("❌ Erro ao buscar contagem de chats não lidos", {
+      error: error instanceof Error ? error.message : "Erro desconhecido",
+      stack: error instanceof Error ? error.stack : undefined,
+    });
+
+    return NextResponse.json(
+      { success: false, error: "Erro ao buscar contagem" },
+      { status: 500 }
+    );
+  }
+}