ci: add GitHub Actions workflow with Azul Zulu JDK 25 on Ubuntu

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: dfa1

.github/workflows/ci.yml

@@ -0,0 +1,26 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Azul Zulu JDK 25
+        uses: actions/setup-java@v4
+        with:
+          distribution: zulu
+          java-version: '25'
+
+      - name: Install flatbuffers and protobuf
+        run: sudo apt-get install -y flatbuffers-compiler protobuf-compiler
+
+      - name: Build and test
+        run: ./mvnw verify