feat: add manual Docker release workflow (#187)

- 新增 docker-release.yml workflow，支持手动触发 Docker 镜像构建
- 从 release.yml 中移除自动 Docker 构建，避免镜像膨胀
- 使用语义化版本号策略（如 v1.0.0）
- 支持多平台构建（linux/amd64, linux/arm64）
- 硬编码公开信息，只需配置 DOCKERHUB_TOKEN secret
- 自动标记版本号和 latest 标签

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude <noreply@anthropic.com>

.github/workflows/docker-release.yml

@@ -0,0 +1,40 @@
+name: Docker Release
+
+on:
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'Version tag (e.g., v1.0.0)'
+        required: true
+        default: 'v1.0.0'
+
+permissions:
+  contents: read
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3
+
+    - name: Log in to Docker Hub
+      uses: docker/login-action@v3
+      with:
+        username: xpzouying
+        password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+    - name: Build and push Docker image
+      uses: docker/build-push-action@v5
+      with:
+        context: .
+        push: true
+        platforms: linux/amd64,linux/arm64
+        tags: |
+          xpzouying/xiaohongshu-mcp:${{ github.event.inputs.version }}
+          xpzouying/xiaohongshu-mcp:latest
+        cache-from: type=gha
+        cache-to: type=gha,mode=max

.github/workflows/release.yml

@@ -142,6 +142,10 @@ jobs:
           ./xiaohongshu-mcp-darwin-arm64
           ```
 
+          ### 🐳 Docker 镜像
+
+          Docker 镜像需要手动触发构建，请到 Actions 页面运行 "Docker Release" workflow。
+
           ### 📊 构建信息
 
           - **Commit**: ${{ github.sha }}