Fix authentication state persistence and admin role display

- Implement complete authentication system with JWT token validation
- Add auth provider with persistent login state across page refreshes
- Create multilingual login/register forms with Material-UI components
- Fix token validation using raw SQL queries to bypass Prisma sync issues
- Add comprehensive error handling for expired/invalid tokens
- Create profile and settings pages with full i18n support
- Add proper user role management (admin/user) with database sync
- Implement secure middleware with CSRF protection and auth checks
- Add debug endpoints for troubleshooting authentication issues
- Fix Zustand store persistence for authentication state

🤖 Generated with [Claude Code](https://claude.ai/code)

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

lib/auth/client.ts

@@ -0,0 +1,29 @@
+export function isTokenExpired(token: string): boolean {
+  try {
+    const payload = JSON.parse(atob(token.split('.')[1])) as { exp?: number }
+    if (!payload || !payload.exp) {
+      console.log('Token has no expiration data')
+      return true
+    }
+
+    const currentTime = Math.floor(Date.now() / 1000)
+    const isExpired = payload.exp < currentTime
+    console.log(`Token expiration check: exp=${payload.exp}, now=${currentTime}, expired=${isExpired}`)
+    return isExpired
+  } catch (error) {
+    console.log('Token validation error:', error)
+    return true
+  }
+}
+
+export function clearExpiredToken(): void {
+  const token = localStorage.getItem('authToken')
+  if (token && isTokenExpired(token)) {
+    console.log('Clearing expired token from localStorage')
+    localStorage.removeItem('authToken')
+  } else if (token) {
+    console.log('Token exists and is valid')
+  } else {
+    console.log('No token in localStorage')
+  }
+}