fix(bank-integration): clearing a mapping row's ERP link resets the registry record

On save, a Bank Integration Customer/Supplier whose mapping row had its
erp_customer / erp_supplier cleared (not just whose row was deleted) is
now flipped back to status=New with mapped_customer/customer_group/
territory/payment_terms cleared — so a registry record never keeps a
phantom mapping.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

jey_erp/jey_erp/doctype/bank_integration/bank_integration.py

@@ -1,8 +1,55 @@
 # Copyright (c) 2026, JeyERP and contributors
 # For license information, please see license.txt
 
+import frappe
 from frappe.model.document import Document
 
 
 class BankIntegration(Document):
-	pass
+	def on_update(self):
+		# Keep the registry records in sync with the mapping child tables:
+		# removing a row OR clearing its erp_customer / erp_supplier flips the
+		# corresponding registry record back to status=New.
+		self._sync_customer_statuses()
+		self._sync_supplier_statuses()
+
+	def _sync_customer_statuses(self):
+		mapped_names = {
+			row.bi_customer_name
+			for row in self.customer_mappings
+			if row.bi_customer_name and row.erp_customer
+		}
+		orphaned = frappe.get_all(
+			"Bank Integration Customer",
+			filters={"status": "Mapped", "parent_bank_integration": self.name},
+			fields=["name"],
+		)
+		for c in orphaned:
+			if c.name not in mapped_names:
+				frappe.db.set_value("Bank Integration Customer", c.name, {
+					"status": "New",
+					"mapped_customer": None,
+					"customer_group": None,
+					"territory": None,
+					"payment_terms": None,
+				}, update_modified=False)
+
+	def _sync_supplier_statuses(self):
+		mapped_names = {
+			row.bi_supplier_name
+			for row in self.supplier_mappings
+			if row.bi_supplier_name and row.erp_supplier
+		}
+		orphaned = frappe.get_all(
+			"Bank Integration Supplier",
+			filters={"status": "Mapped", "parent_bank_integration": self.name},
+			fields=["name"],
+		)
+		for s in orphaned:
+			if s.name not in mapped_names:
+				frappe.db.set_value("Bank Integration Supplier", s.name, {
+					"status": "New",
+					"mapped_supplier": None,
+					"supplier_group": None,
+					"payment_terms": None,
+				}, update_modified=False)