Add super-admin invoices: settings templates and per-business issue flow.

Platform invoice templates live under Settings; each business can list and issue invoices with optional name and a meshkee.com public link.

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

apps/super-admin/src/lib/config.ts

@@ -8,3 +8,9 @@ export function getAdminDomain(): string {
 export function isAllowedAdminHost(hostname = window.location.hostname): boolean {
   return hostname === getAdminDomain()
 }
+
+/** Public invoice URL for platform (super-admin) invoices. */
+export function getPlatformInvoicePublicUrl(invoiceId: string): string {
+  const domain = import.meta.env.VITE_INVOICE_PUBLIC_DOMAIN?.trim() || 'meshkee.com'
+  return `https://${domain}/invoices/${invoiceId}`
+}