test(frontend): add Vitest unit-test harness with first brand helper

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/lib/brand.js

@@ -0,0 +1,4 @@
+export function brandTitle(name) {
+  const trimmed = (name || '').trim()
+  return trimmed || 'RFC'
+}

frontend/src/lib/brand.test.js

@@ -0,0 +1,13 @@
+import { describe, it, expect } from 'vitest'
+import { brandTitle } from './brand.js'
+
+describe('brandTitle', () => {
+  it('returns the deployment name when set', () => {
+    expect(brandTitle('Wiggleverse')).toBe('Wiggleverse')
+  })
+
+  it('falls back to a neutral placeholder when name is empty', () => {
+    expect(brandTitle('')).toBe('RFC')
+    expect(brandTitle(undefined)).toBe('RFC')
+  })
+})

frontend/src/test/setup.js

@@ -0,0 +1 @@
+import '@testing-library/jest-dom'