Add Autosend node with Mail and Contact resources

Implement n8n node for Autosend API with support for:
- Mail resource: Send single and bulk emails with template or custom content
- Contact resource: Create/update contacts (upsert) and get contacts by ID or email
- API key authentication
- Declarative routing following n8n best practices
- Full TypeScript support with proper typing
- Passing all linting checks

nodes/Autosend/Autosend.node.ts

@@ -0,0 +1,71 @@
+import type {
+	INodeType,
+	INodeTypeDescription,
+	INodeExecutionData,
+	IExecuteFunctions,
+} from 'n8n-workflow';
+import { mailFields, mailOperations } from './resources/mail';
+import { contactFields, contactOperations } from './resources/contact';
+
+export class Autosend implements INodeType {
+	description: INodeTypeDescription = {
+		displayName: 'Autosend',
+		name: 'autosend',
+		icon: 'file:autosend.svg',
+		group: ['transform'],
+		version: 1,
+		subtitle: '={{$parameter["operation"] + ": " + $parameter["resource"]}}',
+		description: 'Interact with Autosend API to send emails and manage contacts',
+		defaults: {
+			name: 'Autosend',
+		},
+		inputs: ['main'],
+		outputs: ['main'],
+		credentials: [
+			{
+				name: 'autosendApi',
+				required: true,
+			},
+		],
+		requestDefaults: {
+			baseURL: 'https://api.autosend.com',
+			headers: {
+				Accept: 'application/json',
+				'Content-Type': 'application/json',
+			},
+		},
+		properties: [
+			{
+				displayName: 'Resource',
+				name: 'resource',
+				type: 'options',
+				noDataExpression: true,
+				options: [
+					{
+						name: 'Mail',
+						value: 'mail',
+						description: 'Send emails using Autosend',
+					},
+					{
+						name: 'Contact',
+						value: 'contact',
+						description: 'Manage contacts in Autosend',
+					},
+				],
+				default: 'mail',
+			},
+			...mailOperations,
+			...mailFields,
+			...contactOperations,
+			...contactFields,
+		],
+		usableAsTool: true,
+	};
+
+	async execute(this: IExecuteFunctions): Promise<INodeExecutionData[][]> {
+		// This method is required but the declarative routing handles everything
+		// This is only called if routing doesn't handle the request
+		const items = this.getInputData();
+		return [items];
+	}
+}