Add global navigation search, cancellation policies, and UI improvements

- Add global search in top bar for navigating to dashboard pages
- Add cancellation policy settings (window hours, late fee, deposit refund)
- Display booking policies on customer confirmation page
- Filter API tokens by sandbox/live mode
- Widen settings layout and full-width site builder
- Add help documentation search with OpenAI integration
- Add blocked time ranges API for calendar visualization
- Update business hours settings with holiday management

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/hooks/__tests__/useDateFnsLocale.test.ts

@@ -0,0 +1,113 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { renderHook } from '@testing-library/react';
+import { useDateFnsLocale } from '../useDateFnsLocale';
+import { enUS, de, es, fr } from 'date-fns/locale';
+
+// Mock react-i18next
+vi.mock('react-i18next', () => ({
+  useTranslation: vi.fn(),
+}));
+
+import { useTranslation } from 'react-i18next';
+
+describe('useDateFnsLocale', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it('returns English locale by default', () => {
+    vi.mocked(useTranslation).mockReturnValue({
+      i18n: { language: 'en' },
+      t: vi.fn(),
+      ready: true,
+    } as ReturnType<typeof useTranslation>);
+
+    const { result } = renderHook(() => useDateFnsLocale());
+
+    expect(result.current).toBe(enUS);
+  });
+
+  it('returns German locale for de', () => {
+    vi.mocked(useTranslation).mockReturnValue({
+      i18n: { language: 'de' },
+      t: vi.fn(),
+      ready: true,
+    } as ReturnType<typeof useTranslation>);
+
+    const { result } = renderHook(() => useDateFnsLocale());
+
+    expect(result.current).toBe(de);
+  });
+
+  it('returns Spanish locale for es', () => {
+    vi.mocked(useTranslation).mockReturnValue({
+      i18n: { language: 'es' },
+      t: vi.fn(),
+      ready: true,
+    } as ReturnType<typeof useTranslation>);
+
+    const { result } = renderHook(() => useDateFnsLocale());
+
+    expect(result.current).toBe(es);
+  });
+
+  it('returns French locale for fr', () => {
+    vi.mocked(useTranslation).mockReturnValue({
+      i18n: { language: 'fr' },
+      t: vi.fn(),
+      ready: true,
+    } as ReturnType<typeof useTranslation>);
+
+    const { result } = renderHook(() => useDateFnsLocale());
+
+    expect(result.current).toBe(fr);
+  });
+
+  it('handles language with region code (en-US)', () => {
+    vi.mocked(useTranslation).mockReturnValue({
+      i18n: { language: 'en-US' },
+      t: vi.fn(),
+      ready: true,
+    } as ReturnType<typeof useTranslation>);
+
+    const { result } = renderHook(() => useDateFnsLocale());
+
+    expect(result.current).toBe(enUS);
+  });
+
+  it('handles language with region code (de-DE)', () => {
+    vi.mocked(useTranslation).mockReturnValue({
+      i18n: { language: 'de-DE' },
+      t: vi.fn(),
+      ready: true,
+    } as ReturnType<typeof useTranslation>);
+
+    const { result } = renderHook(() => useDateFnsLocale());
+
+    expect(result.current).toBe(de);
+  });
+
+  it('returns English locale for unknown language', () => {
+    vi.mocked(useTranslation).mockReturnValue({
+      i18n: { language: 'xx' },
+      t: vi.fn(),
+      ready: true,
+    } as ReturnType<typeof useTranslation>);
+
+    const { result } = renderHook(() => useDateFnsLocale());
+
+    expect(result.current).toBe(enUS);
+  });
+
+  it('returns English locale when language is undefined', () => {
+    vi.mocked(useTranslation).mockReturnValue({
+      i18n: { language: undefined },
+      t: vi.fn(),
+      ready: true,
+    } as ReturnType<typeof useTranslation>);
+
+    const { result } = renderHook(() => useDateFnsLocale());
+
+    expect(result.current).toBe(enUS);
+  });
+});