feat: Session is selector for memory nodes (#8736)

packages/@n8n/nodes-langchain/nodes/memory/descriptions.ts

@@ -0,0 +1,35 @@
+import type { INodeProperties } from 'n8n-workflow';
+
+export const sessionIdOption: INodeProperties = {
+	displayName: 'Session ID',
+	name: 'sessionIdType',
+	type: 'options',
+	options: [
+		{
+			// eslint-disable-next-line n8n-nodes-base/node-param-display-name-miscased
+			name: 'Take from previous node automatically',
+			value: 'fromInput',
+			description: 'Looks for an input field called sessionId',
+		},
+		{
+			// eslint-disable-next-line n8n-nodes-base/node-param-display-name-miscased
+			name: 'Define below',
+			value: 'customKey',
+			description: 'Use an expression to reference data in previous nodes or enter static text',
+		},
+	],
+	default: 'fromInput',
+};
+
+export const sessionKeyProperty: INodeProperties = {
+	displayName: 'Key',
+	name: 'sessionKey',
+	type: 'string',
+	default: '',
+	description: 'The key to use to store session ID in the memory',
+	displayOptions: {
+		show: {
+			sessionIdType: ['customKey'],
+		},
+	},
+};