feat(web): add auth+search i18n translations and filter-bar accessibility

Add missing auth and search translation namespaces to vi.json and en.json
that are required by login/register pages and search filter-bar component.
Update filter-bar with useTranslations('search'), aria-labels, and
role="search" for WCAG 2.1 AA compliance.

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

apps/api/package.json

@@ -58,6 +58,7 @@
   },
   "devDependencies": {
     "@nestjs/cli": "^11.0.0",
+    "@nestjs/config": "^4.0.3",
     "@nestjs/schematics": "^11.0.0",
     "@nestjs/testing": "^11.0.0",
     "@types/bcrypt": "^6.0.0",