feat: enhance purchase intentions with chat integration and offer tracking

- Added MongoDB chat/message integration for seller responses
- Improved seller response validation and default messaging
- Integrated automatic chat creation/update when responding to intentions
- Added highest custom offer fields to listing queries and models
- Enhanced listing data with top offer information for buyers

components/admin/AdminSubscriptionTab.tsx

@@ -0,0 +1,50 @@
+"use client";
+
+import { AdminSubscriptionDashboard } from "@/components/admin/subscription-dashboard";
+import { Card, CardContent } from "@/components/ui/card";
+
+interface AdminSubscriptionTabProps {
+  initialTiers: any[];
+  adminUser: {
+    subscription_tier?: {
+      name: string;
+      slug: string;
+    } | null;
+  } | null;
+}
+
+export function AdminSubscriptionTab({
+  initialTiers,
+  adminUser,
+}: AdminSubscriptionTabProps) {
+  return (
+    <div className="space-y-6">
+      <Card>
+        <CardContent className="pt-6">
+          <div className="space-y-2">
+            <h2 className="text-2xl font-semibold tracking-tight">
+              Assinaturas & Permissões
+            </h2>
+            <p className="text-sm text-muted-foreground max-w-2xl">
+              Configure planos, recursos e vincule usuários às assinaturas
+              disponíveis. Todas as alterações são aplicadas imediatamente
+              após salvar.
+            </p>
+            {adminUser?.subscription_tier && (
+              <p className="text-xs text-muted-foreground">
+                Seu plano atual:{" "}
+                <span className="font-semibold uppercase">
+                  {adminUser.subscription_tier.name} (
+                  {adminUser.subscription_tier.slug})
+                </span>
+              </p>
+            )}
+          </div>
+        </CardContent>
+      </Card>
+
+      <AdminSubscriptionDashboard initialTiers={initialTiers} />
+    </div>
+  );
+}
+