fix(tests): resolve 4 vitest failure categories in nextjs frontend

- Fix vitest.config.ts fakemui alias path: ../../fakemui → ../../components/fakemui
  (matches tsconfig.json paths; fixes pagination + get-component-icon tests)
- Add vi.mock('server-only') to route.test.ts to prevent server-only guard
  throwing in jsdom environment
- Replace @jest/globals with vitest in workflow-error-handler and
  multi-tenant-context test files

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontends/nextjs/src/app/api/v1/[...slug]/route.test.ts

@@ -5,7 +5,9 @@
  * Integration tests verify full DBAL execution
  */
 
-import { describe, it, expect } from 'vitest'
+import { describe, it, expect, vi } from 'vitest'
+
+vi.mock('server-only', () => ({}))
 
 describe('API Route /api/v1/[...slug]', () => {
   describe('Route structure', () => {

frontends/nextjs/src/lib/workflow/multi-tenant-context.test.ts

@@ -9,7 +9,7 @@
  * - Security validations
  */
 
-import { describe, it, expect, beforeEach } from '@jest/globals'
+import { describe, it, expect, beforeEach } from 'vitest'
 import {
   MultiTenantContextBuilder,
   createContextFromRequest,

frontends/nextjs/src/lib/workflow/workflow-error-handler.test.ts

@@ -10,7 +10,7 @@
  * - Recovery suggestions and hints
  */
 
-import { describe, it, expect, beforeEach } from '@jest/globals'
+import { describe, it, expect, beforeEach } from 'vitest'
 import {
   WorkflowErrorHandler,
   WorkflowErrorCode,

frontends/nextjs/vitest.config.ts

@@ -16,7 +16,7 @@ export default defineConfig({
       // Use inline to avoid duplicate React instances in tests
       optimizer: {
         web: {
-          include: ['@/fakemui', 'react', 'react-dom']
+          include: ['react', 'react-dom']
         }
       }
     }
@@ -25,8 +25,8 @@ export default defineConfig({
     dedupe: ['react', 'react-dom'],
     alias: [
       // fakemui aliases must be first (more specific matches first)
-      { find: /^@\/fakemui\/(.+)$/, replacement: resolve(__dirname, '../../fakemui/$1') },
-      { find: /^@\/fakemui$/, replacement: resolve(__dirname, '../../fakemui/index.ts') },
+      { find: /^@\/fakemui\/(.+)$/, replacement: resolve(__dirname, '../../components/fakemui/$1') },
+      { find: /^@\/fakemui$/, replacement: resolve(__dirname, '../../components/fakemui/index.ts') },
       // dbal-ui alias for shared UI components
       { find: /^@dbal-ui\/(.+)$/, replacement: resolve(__dirname, '../../dbal/shared/ui/$1') },
       { find: /^@dbal-ui$/, replacement: resolve(__dirname, '../../dbal/shared/ui') },