test(web): add middleware + i18n + messages test suites (GOO-60)

Cover frontend middleware auth/locale logic, i18n config/routing/request/navigation,
and vi/en message parity — 91 new tests across 6 files.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/i18n/__tests__/routing.spec.ts

@@ -0,0 +1,53 @@
+import { describe, expect, it, vi } from 'vitest';
+
+const { mockDefineRouting } = vi.hoisted(() => ({
+  mockDefineRouting: vi.fn((config: unknown) => config),
+}));
+
+// Mock the config module before importing routing
+vi.mock('../config', () => ({
+  locales: ['vi', 'en'] as const,
+  defaultLocale: 'vi' as const,
+}));
+
+// Mock next-intl/routing
+vi.mock('next-intl/routing', () => ({
+  defineRouting: mockDefineRouting,
+}));
+
+import { routing } from '../routing';
+
+describe('i18n/routing', () => {
+  it('calls defineRouting with the correct configuration', () => {
+    expect(mockDefineRouting).toHaveBeenCalledWith({
+      locales: ['vi', 'en'],
+      defaultLocale: 'vi',
+      localePrefix: 'as-needed',
+    });
+  });
+
+  it('exports a routing object', () => {
+    expect(routing).toBeDefined();
+  });
+
+  it('includes all supported locales', () => {
+    const routingConfig = mockDefineRouting.mock.calls[0][0] as {
+      locales: readonly string[];
+    };
+    expect(routingConfig.locales).toEqual(['vi', 'en']);
+  });
+
+  it('sets defaultLocale to vi', () => {
+    const routingConfig = mockDefineRouting.mock.calls[0][0] as {
+      defaultLocale: string;
+    };
+    expect(routingConfig.defaultLocale).toBe('vi');
+  });
+
+  it('uses as-needed locale prefix strategy', () => {
+    const routingConfig = mockDefineRouting.mock.calls[0][0] as {
+      localePrefix: string;
+    };
+    expect(routingConfig.localePrefix).toBe('as-needed');
+  });
+});