Add GitHub Actions workflow

Author: me4502

.github/workflows/gradle.yml

@@ -0,0 +1,42 @@
+name: Gradle Build
+on: [push, pull_request, merge_group]
+
+jobs:
+  build:
+    name: Build CraftBook on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK
+        uses: actions/setup-java@v4
+        with:
+          java-version: 21
+          distribution: 'temurin'
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v3
+        with:
+          cache-read-only: ${{ !(github.ref == 'refs/heads/master' || github.ref == 'refs/heads/five') }}
+
+      - name: Execute Gradle build
+        run: ./gradlew build -s
+
+      - uses: actions/upload-artifact@v4
+        name: Archive Reports
+        if: always()
+        with:
+          name: reports for ${{ matrix.os }}
+          path: '**/build/reports/**'
+
+      - uses: actions/upload-artifact@v4
+        name: Archive Logs
+        if: always()
+        with:
+          name: logs for ${{ matrix.os }}
+          path: '**/*.log'