chore: CI/CD configuration

.forgejo/workflows/docker.yml

@@ -0,0 +1,35 @@
+name: Build & Push (Multi-Arch)
+on:
+  push:
+    branches: [ "main" ]
+    tags: [ "v*" ]
+
+jobs:
+  docker:
+    runs-on: [wsl]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to Registry
+        uses: docker/login-action@v3
+        with:
+          registry: git.j-massing.de
+          username: ${{ secrets.REGISTRY_USER }}
+          password: ${{ secrets.REGISTRY_TOKEN }}
+
+      - name: Build & Push (manifest)
+        run: |
+          IMAGE="git.j-massing.de/hammerfall/ipv6client"
+          TAG="${GITHUB_REF_NAME:-latest}"
+          docker buildx build \
+            --platform linux/arm64/v8 \
+            -t "$IMAGE:$TAG" \
+            -t "$IMAGE:latest" \
+            --push .