CI checks + dependency & code quality improvements

.github/workflows/ci.yml

@@ -0,0 +1,40 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  ci:
+    runs-on: ubuntu-latest
+    env:
+      CI: true
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 24
+          cache: npm
+
+      - name: Install deps
+        run: npm ci
+
+      - name: Lint
+        run: npm run lint
+
+      - name: Build
+        run: npm run build
+
+      - name: Coverage
+        run: npm run coverage

.nvmrc

@@ -0,0 +1 @@
+24