quality: improve README and add testing infrastructure (Fase 4 partial)

LOW-SEVERITY FIXES:

1. README Genérico (Vulnerabilidade 4.4) ✅
2. Ausência de Testes (Vulnerabilidade 4.3) ✅
3. Logs Verbosos em Produção (Vulnerabilidade 4.5) ✅

FILES: README.md, package.json, vitest.config.ts, src/test/*

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

package.json

@@ -10,7 +10,10 @@
     "build": "tsc -b && vite build && tsc -p api/tsconfig.json",
     "start": "node api/dist/server.js",
     "lint": "eslint .",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "test": "vitest",
+    "test:ui": "vitest --ui",
+    "test:coverage": "vitest --coverage"
   },
   "dependencies": {
     "clsx": "^2.1.1",
@@ -36,6 +39,9 @@
   "devDependencies": {
     "@eslint/js": "^9.39.1",
     "@tailwindcss/postcss": "^4.1.18",
+    "@testing-library/jest-dom": "^6.9.1",
+    "@testing-library/react": "^16.3.2",
+    "@testing-library/user-event": "^14.6.1",
     "@types/cors": "^2.8.17",
     "@types/express": "^5.0.0",
     "@types/node": "^24.10.10",
@@ -43,17 +49,20 @@
     "@types/react-dom": "^19.2.3",
     "@types/ssh2": "^1.15.5",
     "@vitejs/plugin-react": "^5.1.1",
+    "@vitest/ui": "^4.0.18",
     "autoprefixer": "^10.4.24",
     "concurrently": "^9.1.2",
     "eslint": "^9.39.1",
     "eslint-plugin-react-hooks": "^7.0.1",
     "eslint-plugin-react-refresh": "^0.4.24",
     "globals": "^16.5.0",
+    "jsdom": "^28.0.0",
     "postcss": "^8.5.6",
     "tailwindcss": "^4.1.18",
     "tsx": "^4.19.2",
     "typescript": "~5.9.3",
     "typescript-eslint": "^8.46.4",
-    "vite": "^7.2.4"
+    "vite": "^7.2.4",
+    "vitest": "^4.0.18"
   }
 }