feat(admin): filter dashboard revenue KPI by current month and completed status

shop/app/admin/page.tsx

@@ -14,12 +14,22 @@ async function getKpis() {
     { count: userCount },
     { count: productCount },
   ] = await Promise.all([
-    adminDb.from('orders').select('total_price, status'),
+    adminDb.from('orders').select('total_price, status, created_at'),
     adminDb.from('profiles').select('*', { count: 'exact', head: true }),
     supabase.from('products').select('*', { count: 'exact', head: true }),
   ])
 
-  const totalRevenue = (orders ?? []).reduce((sum, o) => sum + Number(o.total_price), 0)
+  const now = new Date()
+  const currentYear = now.getFullYear()
+  const currentMonth = now.getMonth()
+
+  const completedOrdersThisMonth = (orders ?? []).filter(o => {
+    if (o.status !== 'completed') return false
+    const orderDate = new Date(o.created_at)
+    return orderDate.getFullYear() === currentYear && orderDate.getMonth() === currentMonth
+  })
+
+  const totalRevenue = completedOrdersThisMonth.reduce((sum, o) => sum + Number(o.total_price), 0)
   const orderCount = (orders ?? []).length
 
   return { totalRevenue, orderCount, userCount: userCount ?? 0, productCount: productCount ?? 0 }
@@ -36,14 +46,14 @@ export default async function AdminDashboard() {
       <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-4">
         <Card className="glass-dark border-white/5">
           <CardHeader className="flex flex-row items-center justify-between space-y-0 pb-2">
-            <CardTitle className="text-sm font-medium text-slate-300">Umsatz gesamt</CardTitle>
+            <CardTitle className="text-sm font-medium text-slate-300">Umsatz aktueller Monat</CardTitle>
             <TrendingUp className="h-4 w-4 text-primary" />
           </CardHeader>
           <CardContent>
             <div className="text-2xl font-bold text-white">
               {new Intl.NumberFormat('de-DE', { style: 'currency', currency: 'EUR' }).format(totalRevenue)}
             </div>
-            <p className="text-xs text-slate-400">Aus allen Bestellungen</p>
+            <p className="text-xs text-slate-400">Nur fertige Bestellungen</p>
           </CardContent>
         </Card>