feat: add purchase invoice batch print page and related components

- Implemented PurchaseInvoiceBatchPrintPage for printing purchase invoices.
- Created InvoicePrintHeader and InvoicePrintFooter components for invoice layout.
- Added invoice layout presets for different styles (Classic, Compact, Modern).
- Developed PurchaseInvoicePaymentDialog for handling payments against invoices.
- Introduced API mocks for company profile and invoice template configuration.
- Added validation functions for company profile and purchase invoices.
- Defined types for company profile, invoice template configuration, and purchase invoices.

Frontend/erp-system/components/sales/SalesInvoicePaymentDialog.tsx

@@ -32,7 +32,8 @@ interface SalesInvoicePaymentDialogProps {
 /** Record a customer payment against an invoice's balance — full or partial, into an existing GL
  * cash/bank account. A Draft invoice is posted first (the backend only accepts payments against a
  * Posted invoice) so this doubles as "confirm and pay in one step" from a list row; an already-Posted
- * invoice skips straight to payment. Modeled on GrnPaymentDialog's "pick an account, submit" shape. */
+ * invoice skips straight to payment. "Pick an account, submit" shape, mirrored by
+ * PurchaseInvoicePaymentDialog on the AP side. */
 export function SalesInvoicePaymentDialog({ invoice, open, onOpenChange, onPaid }: SalesInvoicePaymentDialogProps) {
   const [accounts, setAccounts] = useState<CashAndBankAccountDto[] | null>(null)
   const [glBankAccountId, setGlBankAccountId] = useState("")
@@ -42,7 +43,7 @@ export function SalesInvoicePaymentDialog({ invoice, open, onOpenChange, onPaid
   const [submitting, setSubmitting] = useState(false)
 
   // Reset the form fields for a fresh open (or a different invoice) during render — same
-  // "adjust state while rendering" pattern as GrnPaymentDialog, not inside an effect.
+  // "adjust state while rendering" pattern, not inside an effect.
   const openKey = open && invoice ? `${invoice.salesInvoiceId}` : null
   const [resetFor, setResetFor] = useState<string | null>(null)
   if (openKey !== null && resetFor !== openKey) {