Add prepaid resource credits with prorated deploy billing.

When users delete an app before plan expiry, remaining resources become credits for a new deploy. The deploy calculator shows covered vs additional charges, prices optional services correctly, and prorates extras to days left on the credit.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/app/dashboard/apps/[id]/page.tsx

@@ -566,9 +566,14 @@ export default function AppDetailPage() {
 
   const deleteMutation = useMutation({
     mutationFn: () => api.delete(`/applications/${appId}`),
-    onSuccess: () => {
+    onSuccess: (res) => {
       queryClient.invalidateQueries({ queryKey: ['applications'] });
-      toast.success('Application deleted');
+      queryClient.invalidateQueries({ queryKey: ['resource-credits'] });
+      if (res.data?.resourceCredit) {
+        toast.success('Application deleted. Prepaid resources are on your dashboard.');
+      } else {
+        toast.success('Application deleted');
+      }
       router.push('/dashboard/apps');
     },
     onError: () => toast.error('Failed to delete application'),
@@ -862,7 +867,11 @@ export default function AppDetailPage() {
   const handleDelete = async () => {
     const ok = await confirm({
       title: `Delete "${app.name}"?`,
-      message: 'This will permanently remove:\n• All Kubernetes resources (pods, services, ingress)\n• Database and volumes\n• All deployment records\n• Uploaded source code',
+      message:
+        'This will permanently remove all Kubernetes resources, data, and deployment records.\n\n' +
+        (app.planExpiresAt && new Date(app.planExpiresAt) > new Date()
+          ? 'Your remaining paid resources will appear on the dashboard for use on a new app at no extra charge.'
+          : ''),
       confirmText: 'Delete',
       variant: 'danger',
     });
@@ -937,11 +946,12 @@ export default function AppDetailPage() {
             </>
           )}
           <button onClick={handleDelete} disabled={deleteMutation.isPending} className="btn-danger text-sm disabled:opacity-50">
-                  {deleteMutation.isPending ? <><Clock className="w-3 h-3 inline animate-spin" /></> : 'Delete'}
+            {deleteMutation.isPending ? <><Clock className="w-3 h-3 inline animate-spin" /></> : 'Delete'}
           </button>
         </div>
       </div>
 
+
       {/* Renewal Banner for Expired/Suspended Apps */}
       {needsRenewal && (
         <div className={`rounded-xl p-4 border-2 ${