feat: scaffold Nuxt 3 + Nuxt UI 3

Initialize Nuxt 4 project with @nuxt/ui template including Tailwind CSS v4,
TypeScript, ESLint, and Nuxt UI v3 (via @nuxt/ui package).

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

front-end/.github/workflows/ci.yml

@@ -0,0 +1,34 @@
+name: ci
+
+on: push
+
+jobs:
+  ci:
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+        node: [22]
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4
+
+      - name: Install node
+        uses: actions/setup-node@v6
+        with:
+          node-version: ${{ matrix.node }}
+          cache: pnpm
+
+      - name: Install dependencies
+        run: pnpm install
+
+      - name: Lint
+        run: pnpm run lint
+
+      - name: Typecheck
+        run: pnpm run typecheck