feat(selling): keep cancelled proformas visible with their PDF

Cancelling a proforma should void it, not erase history.

- Persist the Cancelled status on cancel (db_set) and keep the PDF attached
- Proforma tab now lists cancelled proformas with a red status badge, so the
  voided document and its PDF stay reachable for audit

erpnext/public/js/sales_order_proforma.js

@@ -189,7 +189,8 @@ Object.assign(erpnext.proforma, {
 		const list = new frappe.ui.EmbeddedList({
 			wrapper,
 			doctype: "Proforma Invoice",
-			filters: { sales_order: frm.doc.name, docstatus: 1 },
+			// Include cancelled (docstatus 2) so voided proformas stay visible for audit.
+			filters: { sales_order: frm.doc.name, docstatus: ["in", [1, 2]] },
 			fields: ["name", "proforma_date", "grand_total", "status", "proforma_pdf", "sent_on", "currency"],
 			order_by: "creation desc",
 			empty_message: __("No proforma invoices yet."),
@@ -218,7 +219,7 @@ Object.assign(erpnext.proforma, {
 					label: __("Status"),
 					type: "badge",
 					fieldname: "status",
-					color: (row) => (row.status === "Issued" ? "green" : "gray"),
+					color: (row) => (row.status === "Cancelled" ? "red" : "green"),
 				},
 				{
 					type: "actions",

erpnext/selling/doctype/proforma_invoice/proforma_invoice.py

@@ -52,7 +52,7 @@ class ProformaInvoice(Document):
 		self.generate_and_attach_pdf()
 
 	def on_cancel(self) -> None:
-		self.status = "Cancelled"
+		self.db_set("status", "Cancelled")
 
 	def set_total_qty(self) -> None:
 		self.total_qty = sum(flt(item.qty) for item in self.items)

erpnext/selling/doctype/proforma_invoice/test_proforma_invoice.py

@@ -80,6 +80,18 @@ class TestProformaInvoice(ERPNextTestSuite):
 		self.assertEqual(flt(item.amount), 250)
 		self.assertEqual(flt(proforma.grand_total), 250)
 
+	def test_cancelled_proforma_keeps_pdf(self):
+		"""Cancelling voids the proforma but keeps its PDF and status for the audit trail."""
+		sales_order = make_sales_order(qty=10)
+		proforma = self.create_proforma(sales_order, [(sales_order.items[0].name, 4)])
+		pdf = proforma.proforma_pdf
+		self.assertTrue(pdf)
+
+		proforma.cancel()
+		proforma.reload()
+		self.assertEqual(proforma.status, "Cancelled")
+		self.assertEqual(proforma.proforma_pdf, pdf)
+
 	def test_feature_toggle_is_enforced(self):
 		sales_order = make_sales_order(qty=10)
 		frappe.db.set_single_value("Selling Settings", "enable_proforma_invoice", 0)