feat: receipt PDF save and print via html2pdf.js

- Save PDF button downloads receipt directly
- Print button opens PDF in new window and triggers print dialog
- Replaces previous window.print() approach that lost styles
- Receipt generated on demand from transaction data, no file storage needed

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/admin/src/components/pos/pos-payment-dialog.tsx

@@ -10,7 +10,7 @@ import { Label } from '@/components/ui/label'
 import { Separator } from '@/components/ui/separator'
 import { CheckCircle, Printer, Mail } from 'lucide-react'
 import { toast } from 'sonner'
-import { POSReceipt, printReceipt } from './pos-receipt'
+import { POSReceipt, downloadReceiptPDF, printReceiptPDF } from './pos-receipt'
 
 interface POSPaymentDialogProps {
   open: boolean
@@ -98,13 +98,18 @@ export function POSPaymentDialog({ open, onOpenChange, paymentMethod, transactio
       return (
         <Dialog open={open} onOpenChange={() => { setShowReceipt(false); handleDone() }}>
           <DialogContent className="max-w-sm max-h-[90vh] overflow-y-auto print:max-w-none print:max-h-none print:overflow-visible print:shadow-none print:border-none">
-            <div className="print:hidden flex justify-between items-center mb-2">
+            <div className="flex justify-between items-center mb-2">
               <Button variant="ghost" size="sm" onClick={() => setShowReceipt(false)}>Back</Button>
-              <Button size="sm" onClick={printReceipt} className="gap-2">
-                <Printer className="h-4 w-4" />Print
-              </Button>
+              <div className="flex gap-2">
+                <Button variant="outline" size="sm" onClick={() => downloadReceiptPDF(result.transactionNumber)} className="gap-2">
+                  Save PDF
+                </Button>
+                <Button size="sm" onClick={() => printReceiptPDF(result.transactionNumber)} className="gap-2">
+                  <Printer className="h-4 w-4" />Print
+                </Button>
+              </div>
             </div>
-            <div className="print:block">
+            <div id="pos-receipt-print">
               <POSReceipt data={receiptData} config={receiptConfig} />
             </div>
           </DialogContent>

packages/admin/src/components/pos/pos-receipt.tsx

@@ -256,6 +256,48 @@ export function POSReceipt({ data, size = 'thermal', footerText, config }: POSRe
   )
 }
 
-export function printReceipt() {
-  window.print()
+export async function saveReceiptPDF(txnNumber?: string): Promise<Blob | null> {
+  const el = document.getElementById('pos-receipt-print')
+  if (!el) return null
+
+  const html2pdf = (await import('html2pdf.js')).default
+  const blob: Blob = await html2pdf()
+    .set({
+      margin: [4, 4, 4, 4],
+      filename: `receipt-${txnNumber ?? 'unknown'}.pdf`,
+      image: { type: 'jpeg', quality: 0.95 },
+      html2canvas: { scale: 2, useCORS: true },
+      jsPDF: { unit: 'mm', format: [80, 200], orientation: 'portrait' },
+    })
+    .from(el)
+    .outputPdf('blob')
+
+  return blob
+}
+
+export async function downloadReceiptPDF(txnNumber?: string) {
+  const blob = await saveReceiptPDF(txnNumber)
+  if (!blob) return
+
+  const url = URL.createObjectURL(blob)
+  const a = document.createElement('a')
+  a.href = url
+  a.download = `receipt-${txnNumber ?? 'unknown'}.pdf`
+  a.click()
+  URL.revokeObjectURL(url)
+}
+
+export async function printReceiptPDF(txnNumber?: string) {
+  const blob = await saveReceiptPDF(txnNumber)
+  if (!blob) return
+
+  const url = URL.createObjectURL(blob)
+  const printWindow = window.open(url)
+  if (printWindow) {
+    printWindow.onload = () => {
+      printWindow.print()
+    }
+  }
+  // Clean up after a delay
+  setTimeout(() => URL.revokeObjectURL(url), 30000)
 }