feat: Implement user and policy management UI

- Add comprehensive user management with CRUD operations
- Implement policy management with templates and custom JSON
- Create reusable components (ConfirmDialog, LoadingState, EmptyState)
- Add user creation with password validation and credential copying
- Implement policy creation with built-in templates
- Add policy attachment to users functionality
- Include search, filtering, and status management
- Add proper error handling and validation
- Implement Material-UI based responsive design

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

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

frontend/src/utils/auth.ts

@@ -0,0 +1,25 @@
+export const getAuthHeaders = (): Record<string, string> => {
+  const token = localStorage.getItem('authToken');
+  
+  if (!token) {
+    return {};
+  }
+
+  return {
+    'Authorization': `Bearer ${token}`,
+    'Content-Type': 'application/json',
+  };
+};
+
+export const isAuthenticated = (): boolean => {
+  const token = localStorage.getItem('authToken');
+  return !!token;
+};
+
+export const setAuthToken = (token: string): void => {
+  localStorage.setItem('authToken', token);
+};
+
+export const clearAuthToken = (): void => {
+  localStorage.removeItem('authToken');
+};