feat(ZUGFERD): Add dedicated ZUGFERD v1/v2 support and refine invoice format detection logic

ts/formats/cii/zugferd/zugferd.encoder.ts

@@ -0,0 +1,21 @@
+import { CIIBaseEncoder } from '../cii.encoder.js';
+import type { TInvoice } from '../../../interfaces/common.js';
+import { ZUGFERD_PROFILE_IDS } from './zugferd.types.js';
+
+/**
+ * Encoder for ZUGFeRD invoice format
+ */
+export class ZUGFeRDEncoder extends CIIBaseEncoder {
+  /**
+   * Creates ZUGFeRD XML from invoice data
+   * @param invoice Invoice data
+   * @returns ZUGFeRD XML string
+   */
+  public async createXml(invoice: TInvoice): Promise<string> {
+    // Set ZUGFeRD-specific profile ID
+    this.profileId = ZUGFERD_PROFILE_IDS.BASIC;
+    
+    // Use the base CII encoder to create the XML
+    return super.createXml(invoice);
+  }
+}