ci(docker): publish prebuilt image to ghcr

- Build and push multi-arch (amd64/arm64) image on master pushes and version tags
- Generate latest and semver tags via docker metadata action
- Build without pushing on pull requests for validation

.github/workflows/docker.yml

@@ -0,0 +1,58 @@
+name: Docker Image
+
+on:
+  push:
+    branches:
+      - master
+    tags:
+      - "v*"
+  pull_request:
+    branches:
+      - master
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  packages: write
+
+jobs:
+  build-docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v7
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v4
+
+      - name: Login to GitHub Container Registry
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v4
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Docker meta
+        id: docker-meta
+        uses: docker/metadata-action@v6
+        with:
+          images: |
+            ghcr.io/${{ github.repository }}
+          tags: |
+            type=raw,value=latest,enable={{is_default_branch}}
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+
+      - name: Build and push
+        uses: docker/build-push-action@v7
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.docker-meta.outputs.tags }}
+          labels: ${{ steps.docker-meta.outputs.labels }}