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/api/vitest.config.ts

@@ -10,6 +10,29 @@ export default defineConfig({
     env: {
       BCRYPT_ROUNDS: '4',
     },
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'text-summary', 'json-summary', 'lcov', 'clover'],
+      reportsDirectory: './coverage',
+      include: ['src/modules/**/*.ts'],
+      exclude: [
+        'src/**/*.spec.ts',
+        'src/**/*.integration.spec.ts',
+        'src/**/*.mock.ts',
+        'src/**/*.module.ts',
+        'src/**/index.ts',
+        'src/**/__tests__/**',
+        'src/**/__mocks__/**',
+        'src/**/dto/**',
+        'node_modules',
+      ],
+      thresholds: {
+        statements: 60,
+        branches: 50,
+        functions: 60,
+        lines: 60,
+      },
+    },
   },
   resolve: {
     alias: {