feat(tests): enhance test coverage and error handling across various components

- Added a test case in CrowdSecConfig to show improved error message when preset is not cached.
- Introduced a new test suite for the Dashboard component, verifying counts and health status.
- Updated SMTPSettings tests to utilize a shared render function and added tests for backend validation errors.
- Modified Security.audit tests to improve input handling and removed redundant export failure test.
- Refactored Security tests to remove export functionality and ensure correct rendering of components.
- Enhanced UsersPage tests with new scenarios for updating user permissions and manual invite link flow.
- Created a new utility for rendering components with a QueryClient and MemoryRouter for better test isolation.
- Updated go-test-coverage script to improve error handling and coverage reporting.

frontend/src/pages/__tests__/Dashboard.test.tsx

@@ -0,0 +1,60 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { screen } from '@testing-library/react'
+import Dashboard from '../Dashboard'
+import { renderWithQueryClient } from '../../test-utils/renderWithQueryClient'
+
+vi.mock('../../hooks/useProxyHosts', () => ({
+  useProxyHosts: () => ({
+    hosts: [
+      { id: 1, enabled: true },
+      { id: 2, enabled: false },
+    ],
+  }),
+}))
+
+vi.mock('../../hooks/useRemoteServers', () => ({
+  useRemoteServers: () => ({
+    servers: [
+      { id: 1, enabled: true },
+      { id: 2, enabled: true },
+    ],
+  }),
+}))
+
+vi.mock('../../hooks/useCertificates', () => ({
+  useCertificates: () => ({
+    certificates: [
+      { id: 1, status: 'valid' },
+      { id: 2, status: 'expired' },
+    ],
+  }),
+}))
+
+vi.mock('../../api/health', () => ({
+  checkHealth: vi.fn().mockResolvedValue({ status: 'ok', version: '1.0.0' }),
+}))
+
+describe('Dashboard page', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  it('renders counts and health status', async () => {
+    renderWithQueryClient(<Dashboard />)
+
+    expect(await screen.findByText('Dashboard')).toBeInTheDocument()
+    expect(await screen.findByText('1 enabled')).toBeInTheDocument()
+    expect(screen.getByText('2 enabled')).toBeInTheDocument()
+    expect(screen.getByText('1 valid')).toBeInTheDocument()
+    expect(await screen.findByText('Healthy')).toBeInTheDocument()
+  })
+
+  it('shows error state when health check fails', async () => {
+    const { checkHealth } = await import('../../api/health')
+    vi.mocked(checkHealth).mockResolvedValueOnce({ status: 'fail', version: '1.0.0' } as never)
+
+    renderWithQueryClient(<Dashboard />)
+
+    expect(await screen.findByText('Error')).toBeInTheDocument()
+  })
+})