test: improve frontend coverage and exclude backend docker services

frontend/src/hooks/__tests__/useTheme.test.tsx

@@ -0,0 +1,17 @@
+import { describe, it, expect } from 'vitest'
+import { renderHook } from '@testing-library/react'
+import { useTheme } from '../useTheme'
+
+describe('useTheme', () => {
+  it('throws error when used outside ThemeProvider', () => {
+    // Suppress console.error for this test as React logs the error
+    const consoleSpy = vi.spyOn(console, 'error')
+    consoleSpy.mockImplementation(() => {})
+
+    expect(() => {
+      renderHook(() => useTheme())
+    }).toThrow('useTheme must be used within a ThemeProvider')
+
+    consoleSpy.mockRestore()
+  })
+})