REF-23: Add GitHub Actions CI pipeline

.github/workflows/ci.yml

@@ -0,0 +1,35 @@
+name: CI
+
+# REF-23: Build the OIO IDWS / LSBS reference reactor on every PR and on pushes
+# to the mainline branches. Integration tests are NOT run here: the integrationtest/*
+# modules are live end-to-end tests that need Java (and .NET) WSPs running, and the
+# bootstrap scenarios require a MOCES certificate password entered interactively — none
+# of which is available on a CI runner. This job mirrors the supported local build:
+#   mvn clean install -DskipTests   on JDK 8.
+
+on:
+  push:
+    branches: [master, develop]
+  pull_request:
+
+jobs:
+  build:
+    name: Build (JDK 8)
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out
+        uses: actions/checkout@v4
+
+      # JDK 8 is REQUIRED, not just targeted: cxf-codegen's wsdl2java depends on
+      # javax.activation, removed from the JDK after Java 8. On Java 11+ the build
+      # fails with NoClassDefFoundError: javax/activation/DataSource.
+      - name: Set up JDK 8
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: '8'
+          cache: maven
+
+      - name: Build (skip integration tests)
+        run: mvn --batch-mode --no-transfer-progress clean install -DskipTests