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

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

frontend/package.json

@@ -6,7 +6,9 @@
   "scripts": {
     "dev": "vite",
     "build": "vite build",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "test": "vitest",
+    "test:run": "vitest run"
   },
   "dependencies": {
     "@amplitude/unified": "^1.1.9",
@@ -27,9 +29,13 @@
     "react-router-dom": "^7.2.0"
   },
   "devDependencies": {
+    "@testing-library/jest-dom": "^6.6.0",
+    "@testing-library/react": "^16.1.0",
     "@types/react": "^19.2.14",
     "@types/react-dom": "^19.2.3",
     "@vitejs/plugin-react": "^6.0.1",
-    "vite": "^8.0.12"
+    "jsdom": "^25.0.0",
+    "vite": "^8.0.12",
+    "vitest": "^3.0.0"
   }
 }

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'

frontend/vitest.config.js

@@ -0,0 +1,12 @@
+import { defineConfig } from 'vitest/config'
+import react from '@vitejs/plugin-react'
+
+export default defineConfig({
+  plugins: [react()],
+  test: {
+    environment: 'jsdom',
+    globals: true,
+    setupFiles: ['./src/test/setup.js'],
+    include: ['src/**/*.test.{js,jsx}'],
+  },
+})