Add tests for auth storage logic and i18n routing configuration

- Added comprehensive unit tests for `auth/storage` to handle SSR, E2E paths, storage method selection, and error handling.
- Introduced tests for `i18n/routing` to validate locale configuration, navigation hooks, and link preservation.
- Updated Jest coverage exclusions to include `

frontend/tests/lib/i18n/routing.test.ts

@@ -0,0 +1,38 @@
+/**
+ * Tests for i18n routing configuration
+ */
+
+import { routing, Link, usePathname, useRouter } from '@/lib/i18n/routing';
+import { render, screen } from '@testing-library/react';
+
+describe('i18n routing', () => {
+  it('exposes supported locales and defaultLocale', () => {
+    expect(routing.locales).toEqual(['en', 'it']);
+    expect(routing.defaultLocale).toBe('en');
+    // Using "always" strategy for clarity
+    // @ts-expect-error - localePrefix not in typed export
+    expect(routing.localePrefix).toBe('always');
+  });
+
+  it('provides Link wrapper that preserves href', () => {
+    render(
+      <Link href="/en/about" data-testid="test-link">
+        About
+      </Link>
+    );
+    const el = screen.getByTestId('test-link') as HTMLAnchorElement;
+    expect(el.tagName).toBe('A');
+    expect(el.getAttribute('href')).toBe('/en/about');
+    expect(screen.getByText('About')).toBeInTheDocument();
+  });
+
+  it('provides navigation hooks', () => {
+    const pathname = usePathname();
+    const router = useRouter();
+
+    expect(pathname).toBe('/en/test');
+    expect(router).toEqual(
+      expect.objectContaining({ push: expect.any(Function), replace: expect.any(Function) })
+    );
+  });
+});

frontend/tests/lib/i18n/routing.test.tsx

@@ -0,0 +1,39 @@
+/**
+ * Tests for i18n routing configuration
+ */
+
+import { routing, Link, usePathname, useRouter, redirect } from '@/lib/i18n/routing';
+import { render, screen } from '@testing-library/react';
+
+describe('i18n routing', () => {
+  it('exposes supported locales and defaultLocale', () => {
+    expect(routing.locales).toEqual(['en', 'it']);
+    expect(routing.defaultLocale).toBe('en');
+    // Using "always" strategy for clarity (property exists in the config object)
+    // @ts-expect-error typed export may not include localePrefix
+    expect(routing.localePrefix).toBe('always');
+  });
+
+  it('provides Link wrapper that preserves href and children', () => {
+    render(
+      <Link href="/en/about" data-testid="test-link">
+        About
+      </Link>
+    );
+    const el = screen.getByTestId('test-link') as HTMLAnchorElement;
+    expect(el.tagName).toBe('A');
+    expect(el.getAttribute('href')).toBe('/en/about');
+    expect(screen.getByText('About')).toBeInTheDocument();
+  });
+
+  it('provides navigation hooks and redirect function', () => {
+    const pathname = usePathname();
+    const router = useRouter();
+
+    expect(pathname).toBe('/en/test');
+    expect(typeof redirect).toBe('function');
+    expect(router).toEqual(
+      expect.objectContaining({ push: expect.any(Function), replace: expect.any(Function) })
+    );
+  });
+});