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/[chatId]/route.ts

@@ -0,0 +1,76 @@
+/**
+ * GET /api/chats/[chatId] - Busca detalhes de um chat específico
+ */
+
+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,
+  { params }: { params: Promise<{ chatId: string }> }
+) {
+  try {
+    const authResult = await requireAuth(request);
+    if (authResult instanceof NextResponse) return authResult;
+    const auth = authResult;
+
+    const { chatId } = await params;
+
+    await connectMongoDB();
+
+    // Buscar chat
+    const chat = await Chat.findOne({ chat_id: chatId });
+
+    if (!chat) {
+      return NextResponse.json(
+        { success: false, error: "Chat não encontrado" },
+        { status: 404 }
+      );
+    }
+
+    // Verificar se o usuário pertence ao chat
+    if (chat.buyer_id !== auth.userId && chat.seller_id !== auth.userId) {
+      return NextResponse.json(
+        { success: false, error: "Você não tem permissão para acessar este chat" },
+        { status: 403 }
+      );
+    }
+
+    return NextResponse.json(
+      {
+        success: true,
+        chat: {
+          chat_id: chat.chat_id,
+          listing_id: chat.listing_id,
+          buyer_id: chat.buyer_id,
+          seller_id: chat.seller_id,
+          created_at: chat.created_at.toISOString(),
+          updated_at: chat.updated_at.toISOString(),
+          last_message_at: chat.last_message_at?.toISOString() || null,
+          last_message_preview: chat.last_message_preview,
+          buyer_unread_count: chat.buyer_unread_count,
+          seller_unread_count: chat.seller_unread_count,
+          is_active: chat.is_active,
+          listing_cache: chat.listing_cache,
+          buyer_cache: chat.buyer_cache,
+          seller_cache: chat.seller_cache,
+        },
+      },
+      { status: 200 }
+    );
+  } catch (error) {
+    secureLogger.error("❌ Erro ao buscar chat", {
+      error: error instanceof Error ? error.message : "Erro desconhecido",
+      stack: error instanceof Error ? error.stack : undefined,
+    });
+
+    return NextResponse.json(
+      { success: false, error: "Erro ao buscar chat" },
+      { status: 500 }
+    );
+  }
+}
+