Add CI workflow with Node.js matrix testing and package manager detection

.github/workflows/ci-tests.yml

@@ -0,0 +1,77 @@
+# GitHub Actions workflow: CI - run tests for Node/React app
+# Triggers on push to main/develop and on pull requests. Detects package manager (npm/yarn/pnpm),
+# caches dependencies, installs, and runs tests once (non-watch).
+name: CI - Tests
+
+on:
+  push:
+    branches: [ "main", "develop" ]
+  pull_request:
+    branches: [ "main", "develop" ]
+  workflow_dispatch:
+
+jobs:
+  test:
+    name: Test on Node.js ${{ matrix.node-version }}
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    strategy:
+      matrix:
+        node-version: [18.x, 20.x]
+
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v4
+
+      - name: Detect package manager and lockfile
+        id: detect
+        shell: bash
+        run: |
+          # Default to npm if nothing is found
+          if [ -f pnpm-lock.yaml ]; then
+            echo "manager=pnpm" >> $GITHUB_OUTPUT
+            echo "lockfile=pnpm-lock.yaml" >> $GITHUB_OUTPUT
+            echo "install=pnpm install --frozen-lockfile" >> $GITHUB_OUTPUT
+          elif [ -f yarn.lock ]; then
+            echo "manager=yarn" >> $GITHUB_OUTPUT
+            echo "lockfile=yarn.lock" >> $GITHUB_OUTPUT
+            echo "install=yarn install --frozen-lockfile" >> $GITHUB_OUTPUT
+          elif [ -f package-lock.json ]; then
+            echo "manager=npm" >> $GITHUB_OUTPUT
+            echo "lockfile=package-lock.json" >> $GITHUB_OUTPUT
+            echo "install=npm ci" >> $GITHUB_OUTPUT
+          else
+            # Fallback to npm if no lockfile found
+            echo "manager=npm" >> $GITHUB_OUTPUT
+            echo "lockfile=package-lock.json" >> $GITHUB_OUTPUT
+            echo "install=npm install" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Setup Node.js and dependency cache
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          cache: ${{ steps.detect.outputs.manager }}
+          cache-dependency-path: ${{ steps.detect.outputs.lockfile }}
+
+      - name: Install dependencies
+        shell: bash
+        run: |
+          echo "Using package manager: ${{ steps.detect.outputs.manager }}"
+          echo "Running install command: ${{ steps.detect.outputs.install }}"
+          eval "${{ steps.detect.outputs.install }}"
+
+      - name: Run tests
+        env:
+          CI: true
+        shell: bash
+        run: |
+          echo "Running test script using ${{ steps.detect.outputs.manager }}"
+          if [ "${{ steps.detect.outputs.manager }}" = "npm" ]; then
+            npm test
+          elif [ "${{ steps.detect.outputs.manager }}" = "yarn" ]; then
+            yarn test
+          else
+            pnpm test
+          fi