Add GitHub Action for automated backend deployment

- Build and push Docker image on PR merge or manual trigger
- Deploy to production server via SSH
- Uses Makefile for consistent build process

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

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/deploy-backend.yml

@@ -0,0 +1,55 @@
+name: Deploy Backend API
+
+on:
+  pull_request:
+    types: [closed]
+    branches:
+      - main
+      - master
+  workflow_dispatch:
+
+jobs:
+  build-and-push:
+    # Only run if PR was merged or manually triggered
+    if: github.event_name == 'workflow_dispatch' || (github.event.pull_request.merged == true)
+    runs-on: ubuntu-latest
+    
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+      
+      - name: Build and push API image using Makefile
+        run: |
+          make build-push-api
+
+  deploy:
+    needs: build-and-push
+    runs-on: ubuntu-latest
+    
+    steps:
+      - name: Deploy to Production Server
+        uses: appleboy/ssh-action@v1.0.3
+        with:
+          host: qingsu.chat
+          username: root
+          key: ${{ secrets.SSH_PRIVATE_KEY }}
+          port: 22
+          script: |
+            cd /root/projects/jim-dify
+            git fetch origin
+            git reset --hard origin/$(git branch --show-current)
+            cd docker
+            export HTTP_PROXY=http://host.docker.internal:1081
+            export HTTPS_PROXY=http://host.docker.internal:1081
+            export NO_PROXY=weaviate,sandbox,plugin_daemon,localhost,127.0.0.1
+            docker compose pull
+            docker compose up -d --force-recreate nginx web api worker scheduler