chore: scaffold Nuxt 4 app with Postgres, tooling and health route

Nuxt 4 (app/ structure) + TypeScript, ESLint, Vitest + @nuxt/test-utils,
Drizzle + pg, a /api/health route with a DB ping, and a dev docker-compose
(app + Postgres). Verified: pnpm test, lint, and build pass; the built
server answers /api/health.

app/pages/dashboard.vue

@@ -0,0 +1,6 @@
+<template>
+  <main>
+    <h1>Andon — weak point dashboard</h1>
+    <p>The red-dot defect map lands in Task 7.</p>
+  </main>
+</template>