Add CI workflow (maven test)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jamie-keyin

.github/workflows/ci.yml

@@ -0,0 +1,32 @@
+name: CI
+
+on:
+  push:
+    branches: ["main", "feature/**"]
+  pull_request:
+    branches: ["main"]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up JDK 26
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: '26'
+
+      - name: Cache Maven local repository
+        uses: actions/cache@v4
+        with:
+          path: ~/.m2/repository
+          key: ${{ runner.os }}-m2-${{ hashFiles('**/pom.xml') }}
+          restore-keys: |
+            ${{ runner.os }}-m2-
+
+      - name: Build and run tests
+        run: mvn -B -U test