Add CI pipeline for backend frontend and Docker builds

.github/workflows/ci.yml

@@ -0,0 +1,70 @@
+name: SyncForge CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  backend-tests:
+    name: Backend Tests
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Java 21
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: "21"
+          cache: maven
+
+      - name: Run backend tests
+        run: mvn -B test
+
+  frontend-build:
+    name: Frontend Build
+    runs-on: ubuntu-latest
+
+    defaults:
+      run:
+        working-directory: frontend
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js 22
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+          cache: npm
+          cache-dependency-path: frontend/package-lock.json
+
+      - name: Install frontend dependencies
+        run: npm ci
+
+      - name: Build frontend
+        run: npm run build
+
+  docker-build:
+    name: Docker Build
+    runs-on: ubuntu-latest
+    needs:
+      - backend-tests
+      - frontend-build
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Validate Docker Compose
+        run: docker compose config
+
+      - name: Build Docker images
+        run: docker compose build