Upgrade to Node 24 with shared test workflow

Migrate test.yml to use shared reusable workflow from
activeprospect/github-action-workflows. Add .nvmrc and engines field.

Author: johnrb2

.github/workflows/test.yml

@@ -2,22 +2,9 @@ name: Node.js CI
 on: push
 jobs:
   test:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        node-version: [16.x, 18.x, latest]
-    env:
+    uses: activeprospect/github-action-workflows/.github/workflows/test.yml@master
+    with:
+      codecov: true
+    secrets:
       NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
-    steps:
-    - uses: actions/checkout@v3
- 
-    - name: Use Node.js ${{ matrix.node-version }}
-      uses: actions/setup-node@v3
-      with:
-        node-version: ${{ matrix.node-version }}
-    - run: npm install
-    - name: Run tests
-      run: npx nyc@latest --reporter=lcov npm test
-    - uses: codecov/codecov-action@v1
-      with:
-        token: ${{ secrets.CODECOV_TOKEN }}
+      CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}

.nvmrc

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

package.json

@@ -30,5 +30,8 @@
   "bugs": {
     "url": "https://github.com/hughsk/flat/issues"
   },
-  "homepage": "https://github.com/hughsk/flat"
+  "homepage": "https://github.com/hughsk/flat",
+  "engines": {
+    "node": ">=20"
+  }
 }