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.

components/messages/MessagesBell.tsx

@@ -0,0 +1,93 @@
+"use client";
+
+import { useState, useEffect } from "react";
+import { MessageCircle } from "lucide-react";
+import { Button } from "@/components/ui/button";
+import { Badge } from "@/components/ui/badge";
+import { useSession } from "@/lib/hooks/use-session";
+import { MessagesPanel } from "./MessagesPanel";
+
+interface MessagesBellProps {
+  className?: string;
+}
+
+export function MessagesBell({ className }: MessagesBellProps) {
+  const { user } = useSession();
+  const [unreadUsersCount, setUnreadUsersCount] = useState(0);
+  const [isOpen, setIsOpen] = useState(false);
+
+  // Buscar contagem de usuários únicos com mensagens não vistas
+  const fetchUnreadCount = async () => {
+    if (!user) return;
+
+    try {
+      const res = await fetch("/api/chats/unread-count", {
+        credentials: "include",
+      });
+      if (res.ok) {
+        const data = await res.json();
+        if (data.success) {
+          setUnreadUsersCount(data.count);
+        }
+      }
+    } catch (error) {
+      console.error("[CHAT-DEBUG] Erro ao buscar contagem de chats:", error);
+    }
+  };
+
+  // Polling automático a cada 30 segundos
+  useEffect(() => {
+    if (!user) return;
+
+    fetchUnreadCount();
+
+    const interval = setInterval(() => {
+      fetchUnreadCount();
+    }, 30000); // 30 segundos
+
+    return () => clearInterval(interval);
+  }, [user]);
+
+  // Atualizar contagem quando abrir/fechar
+  useEffect(() => {
+    if (isOpen) {
+      fetchUnreadCount();
+    }
+  }, [isOpen]);
+
+  // Marcar como visto quando abrir
+  const handleOpenChange = (open: boolean) => {
+    setIsOpen(open);
+  };
+
+  if (!user) {
+    return null;
+  }
+
+  return (
+    <>
+      <Button
+        variant="ghost"
+        size="icon"
+        className={`relative ${className}`}
+        onClick={() => handleOpenChange(true)}
+      >
+        <MessageCircle className="h-5 w-5" />
+        {unreadUsersCount > 0 && (
+          <Badge
+            variant="destructive"
+            className="absolute -top-1 -right-1 h-5 w-5 flex items-center justify-center p-0 text-xs rounded-full animate-pulse"
+          >
+            {unreadUsersCount > 99 ? "99+" : unreadUsersCount}
+          </Badge>
+        )}
+      </Button>
+      
+      <MessagesPanel
+        open={isOpen}
+        onOpenChange={handleOpenChange}
+        onUnreadCountChange={setUnreadUsersCount}
+      />
+    </>
+  );
+}