Add label printing functionality and error handling in stock and label flows

tests/api/labels.test.js

@@ -0,0 +1,23 @@
+import { describe, expect, it } from 'vitest';
+
+import { formatPrintErrorMessage } from '../../src/api/labels.js';
+
+describe('api/labels formatPrintErrorMessage', () => {
+  it('maps printer_unavailable payload to user-friendly message', () => {
+    const message = formatPrintErrorMessage({
+      status: 503,
+      payload: {
+        code: 'printer_unavailable',
+        message: 'Backend says unavailable',
+        details: { printer: 'Office Zebra' },
+      },
+    });
+
+    expect(message).toBe('Printer is unavailable. (printer: Office Zebra)');
+  });
+
+  it('falls back to generic message when payload is missing', () => {
+    const message = formatPrintErrorMessage(new Error('Something failed'));
+    expect(message).toBe('Something failed');
+  });
+});