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>

package.json

@@ -26,6 +26,7 @@
     "build": "turbo run build",
     "lint": "eslint .",
     "test": "turbo run test",
+    "test:coverage": "turbo run test:coverage",
     "typecheck": "turbo run typecheck",
     "format": "prettier --write .",
     "format:check": "prettier --check .",