feat: Add AI tool building capabilities (#7336)

Github issue / Community forum post (link here to close automatically):
https://community.n8n.io/t/langchain-memory-chat/23733

---------

Signed-off-by: Oleg Ivaniv <me@olegivaniv.com>
Co-authored-by: Oleg Ivaniv <me@olegivaniv.com>
Co-authored-by: Val <68596159+valya@users.noreply.github.com>
Co-authored-by: Alex Grozav <alex@grozav.com>
Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <aditya@netroy.in>
Co-authored-by: Deborah <deborah@starfallprojects.co.uk>
Co-authored-by: Jesper Bylund <mail@jesperbylund.com>
Co-authored-by: Jon <jonathan.bennetts@gmail.com>
Co-authored-by: Michael Kret <88898367+michael-radency@users.noreply.github.com>
Co-authored-by: Giulio Andreini <andreini@netseven.it>
Co-authored-by: Mason Geloso <Mason.geloso@gmail.com>
Co-authored-by: Mason Geloso <hone@Masons-Mac-mini.local>
Co-authored-by: Mutasem Aldmour <mutasem@n8n.io>

packages/@n8n/nodes-langchain/nodes/trigger/ManualChatTrigger/ManualChatTrigger.node.ts

@@ -0,0 +1,68 @@
+import {
+	type ITriggerFunctions,
+	type INodeType,
+	type INodeTypeDescription,
+	type ITriggerResponse,
+	NodeConnectionType,
+} from 'n8n-workflow';
+
+export class ManualChatTrigger implements INodeType {
+	description: INodeTypeDescription = {
+		displayName: 'Manual Chat Trigger',
+		name: 'manualChatTrigger',
+		icon: 'fa:comments',
+		group: ['trigger'],
+		version: [1, 1.1],
+		description: 'Runs the flow on new manual chat message',
+		eventTriggerDescription: '',
+		maxNodes: 1,
+		defaults: {
+			name: 'On new manual Chat Message',
+			color: '#909298',
+		},
+		codex: {
+			categories: ['Core Nodes'],
+			resources: {
+				primaryDocumentation: [
+					{
+						url: 'https://docs.n8n.io/integrations/builtin/core-nodes/n8n-nodes-langchain.manualchattrigger/',
+					},
+				],
+			},
+			subcategories: {
+				'Core Nodes': ['Other Trigger Nodes'],
+			},
+		},
+		inputs: [],
+		outputs: [NodeConnectionType.Main],
+		properties: [
+			{
+				displayName:
+					'This node is where a manual chat workflow execution starts. To make one, go back to the canvas and click ‘Chat’',
+				name: 'notice',
+				type: 'notice',
+				default: '',
+			},
+			{
+				// eslint-disable-next-line n8n-nodes-base/node-param-display-name-miscased
+				displayName: 'Chat and execute workflow',
+				name: 'openChat',
+				type: 'button',
+				typeOptions: {
+					action: 'openChat',
+				},
+				default: '',
+			},
+		],
+	};
+
+	async trigger(this: ITriggerFunctions): Promise<ITriggerResponse> {
+		const manualTriggerFunction = async () => {
+			this.emit([this.helpers.returnJsonArray([{}])]);
+		};
+
+		return {
+			manualTriggerFunction,
+		};
+	}
+}