build: 分离开发与发布环境的 Docker 构建配置

- 新增 Dockerfile.release 用于生产环境，仅包含运行所需的最小依赖
- 重构原 Dockerfile 为多阶段构建，集成前端构建与后端编译
- 更新 .goreleaser.yaml 以使用新的发布镜像配置
- 新增 GitHub Actions 工作流用于自动构建和推送 Docker 镜像

.github/workflows/docker-build.yml

@@ -0,0 +1,62 @@
+name: Docker Build and Push
+
+on:
+  push:
+    branches: [ "main", "master" ]
+    paths-ignore:
+      - 'docs/**'
+      - '**.md'
+  pull_request:
+    branches: [ "main", "master" ]
+    paths-ignore:
+      - 'docs/**'
+      - '**.md'
+
+env:
+  REGISTRY: ghcr.io
+  # Use message-nest to match release workflow naming, or use ${{ github.repository }} for default
+  IMAGE_NAME: message-nest
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to the Container registry
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ github.repository_owner }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=raw,value=latest,enable=${{ github.ref == 'refs/heads/main' || github.ref == 'refs/heads/master' }}
+            type=ref,event=branch
+            type=ref,event=pr
+            type=sha
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: ./Dockerfile
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max