feat: Implement API modules for admin, auth, exam, result, and setup functionalities

- Created adminApi.ts for admin-related operations including user management and site settings.
- Developed authApi.ts for authentication processes such as registration, login, and profile management.
- Added examApi.ts for handling exam CRUD operations.
- Introduced resultApi.ts for managing results submission and retrieval.
- Established setupApi.ts for initial setup processes and status checks.
- Created ErrorBoundary component to handle rendering errors gracefully in the frontend.
- Re-exported shared API utilities in index.ts for easier access.

frontend/src/components/SetupWizard.tsx

@@ -1,5 +1,6 @@
 import { useState } from 'react'
-import { apiFetch, setToken } from '../utils/api'
+import { setToken } from '../utils/api'
+import * as setupApi from '../api/setupApi'
 
 interface Props {
   onComplete: () => void
@@ -51,29 +52,17 @@ export default function SetupWizard({ onComplete }: Readonly<Props>) {
     setError(null)
     setSubmitting(true)
     try {
-      const data = await apiFetch<{
-        message: string
-        token: string
-        user: {
-          id: number
-          email: string
-          displayName: string
-          role: 'user' | 'admin'
-        }
-      }>('/api/setup', {
-        method: 'POST',
-        body: JSON.stringify({
-          email,
-          password,
-          displayName: displayName.trim(),
-          smtpHost,
-          smtpPort,
-          smtpUser,
-          smtpPass,
-          smtpFrom: smtpFrom || 'BrainWave <noreply@brainwave.local>',
-          smtpSecure,
-          appUrl,
-        }),
+      const data = await setupApi.completeSetup({
+        email,
+        password,
+        displayName: displayName.trim(),
+        smtpHost,
+        smtpPort,
+        smtpUser,
+        smtpPass,
+        smtpFrom: smtpFrom || 'BrainWave <noreply@brainwave.local>',
+        smtpSecure,
+        appUrl,
       })
       setToken(data.token)
       onComplete()