✨ feat(frontend): scaffold minimal Nuxt 3 frontend with healthz dashboard

First step toward a Vue 3 / Nuxt 3 / Playwright e2e frontend stack.

Adds:
- frontend/ - Nuxt 3 scaffold (TypeScript)
- frontend/components/HealthDashboard.vue - calls /api/healthz, shows status/version/uptime/timestamp
- frontend/pages/index.vue - landing page using HealthDashboard
- frontend/nuxt.config.ts - dev proxy /api -> http://localhost:8080
- frontend/playwright.config.ts + tests/e2e/health.spec.ts - 1 baseline e2e test
- .gitignore - frontend artifacts excluded

Out of scope (separate PRs):
- Storybook
- Design system / Tailwind
- Auth pages
- Production build / deploy config

Generated ~95% in autonomy by Mistral Vibe via ICM workspace
~/Work/Vibe/workspaces/frontend-nuxt-scaffold/.

Trainer (Claude) finalized commit/PR (Mistral hit max-turns or trainer takeover).

🤖 Co-Authored-By: Mistral Vibe (devstral-2 / mistral-medium-3.5)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/nuxt.config.ts

@@ -0,0 +1,11 @@
+export default defineNuxtConfig({
+  devtools: { enabled: true },
+  nitro: {
+    devProxy: {
+      '/api': {
+        target: 'http://localhost:8080',
+        changeOrigin: true,
+      },
+    },
+  },
+})