Add invoice PDF generation with dompdf

Install barryvdh/laravel-dompdf, create professional invoice Blade template
with EZSCALE branding, add download endpoints for customer billing and admin
invoice pages.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

website/resources/ts/Pages/Admin/Invoices/Show.vue

@@ -120,11 +120,9 @@ function formatDateTime(dateStr: string | null): string {
 
       <div class="d-flex gap-2">
         <VBtn
-          v-if="invoice.invoice_pdf"
           color="info"
           variant="tonal"
-          :href="invoice.invoice_pdf"
-          target="_blank"
+          :href="`/invoices/${invoice.id}/download`"
         >
           <VIcon icon="tabler-download" start />
           Download PDF

website/resources/ts/Pages/Billing/Invoices.vue

@@ -54,7 +54,15 @@ defineProps<Props>()
               </td>
               <td class="text-end">${{ parseFloat(invoice.total).toFixed(2) }}</td>
               <td class="text-end">
-                <a :href="`/billing/invoices/${invoice.id}/download`" class="text-primary text-decoration-none">Download</a>
+                <VBtn
+                  :href="`/billing/invoices/${invoice.id}/download`"
+                  color="primary"
+                  variant="tonal"
+                  size="small"
+                >
+                  <VIcon icon="tabler-download" start />
+                  PDF
+                </VBtn>
               </td>
             </tr>
           </tbody>