fix(billing): round the recurring figure the same way as the total

The note rounded VAT after aggregating while the total rounded per order, so
cent-level prices made the two disagree — and a customer who spots that stops
trusting every other number on the page.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

resources/views/livewire/billing.blade.php

@@ -72,7 +72,9 @@
             @php
                 $net = $pending->sum('amount_cents');
                 $gross = $pending->sum(fn ($o) => $o->grossCents());
-                $recurringNet = $pending->filter->isRecurring()->sum('amount_cents');
+                // Summed from the same per-order rounding the total uses: rounding
+                // after aggregating would let the two figures disagree by a cent.
+                $recurringGross = $pending->filter->isRecurring()->sum(fn ($o) => $o->grossCents());
             @endphp
             <div class="space-y-1.5 border-t border-line bg-surface-2 px-5 py-3.5 text-sm">
                 <div class="flex items-center justify-between text-muted">
@@ -87,11 +89,11 @@
                     <span>{{ __('billing.cart.total_gross') }}</span>
                     <span class="font-mono">{{ $eur($gross) }}</span>
                 </div>
-                @if ($recurringNet > 0)
+                @if ($recurringGross > 0)
                     {{-- The number that actually matters every month, kept apart
                          from a one-off traffic top-up in the same cart. --}}
                     <p class="pt-1 text-xs text-faint">
-                        {{ __('billing.cart.recurring_note', ['amount' => $eur((int) round($recurringNet * (1 + \App\Models\Order::taxRate())))]) }}
+                        {{ __('billing.cart.recurring_note', ['amount' => $eur($recurringGross)]) }}
                     </p>
                 @endif
             </div>

tests/Feature/CartTest.php

@@ -132,3 +132,20 @@ it('separates what recurs from a one-off top-up', function () {
 
     Livewire\Livewire::actingAs($user)->test(Billing::class)->assertSee($expected);
 });
+
+it('keeps the recurring figure consistent with the total to the cent', function () {
+    [$customer, $user] = cartCustomer();
+    config()->set('provisioning.tax.rate_percent', 20);
+
+    // Cent-level prices: rounding after aggregating instead of per order makes
+    // the two figures disagree, and a customer who spots that stops trusting
+    // every other number on the page.
+    Order::factory()->for($customer)->create(['type' => 'storage', 'amount_cents' => 3, 'status' => 'pending']);
+    Order::factory()->for($customer)->create(['type' => 'storage', 'amount_cents' => 3, 'status' => 'pending']);
+
+    $expected = Illuminate\Support\Number::currency(0.08, in: 'EUR', locale: 'de');
+
+    Livewire\Livewire::actingAs($user)->test(Billing::class)
+        ->assertSee($expected)                                                     // total gross
+        ->assertSee(__('billing.cart.recurring_note', ['amount' => $expected]));   // and the note
+});