fix(ci): replace appleboy/ssh-action with native SSH for deploy

Closes #38
Assisted-by: Claude:claude-sonnet-4-6

.github/workflows/ui.yml

@@ -101,20 +101,21 @@ jobs:
 
     steps:
       - name: SSH deploy
-        uses: appleboy/ssh-action@v1.0.3
-        with:
-          host: ${{ secrets.SSH_HOST }}
-          username: ${{ secrets.SSH_USER }}
-          key: ${{ secrets.SSH_PRIVATE_KEY }}
-          port: ${{ secrets.SSH_PORT }}
-          script: |
-            docker-user << 'EOF'
-            docker pull ${{ needs.docker.outputs.sha_tag }}
-            docker stop dashboard-ui 2>/dev/null || true
-            docker rm   dashboard-ui 2>/dev/null || true
-            docker run -d \
-              --name dashboard-ui \
-              --restart unless-stopped \
-              -p 80:80 \
-              ${{ needs.docker.outputs.sha_tag }}
-            EOF
+        env:
+          SSH_KEY: ${{ secrets.SSH_PRIVATE_KEY }}
+          SHA_TAG: ${{ needs.docker.outputs.sha_tag }}
+        run: |
+          echo "$SSH_KEY" > /tmp/deploy_key
+          chmod 600 /tmp/deploy_key
+          ssh -i /tmp/deploy_key \
+            -p ${{ secrets.SSH_PORT }} \
+            -o StrictHostKeyChecking=no \
+            -o IdentitiesOnly=yes \
+            ${{ secrets.SSH_USER }}@${{ secrets.SSH_HOST }} \
+            "docker-user << 'EOF'
+          docker pull $SHA_TAG
+          docker stop dashboard-ui 2>/dev/null || true
+          docker rm   dashboard-ui 2>/dev/null || true
+          docker run -d --name dashboard-ui --restart unless-stopped -p 80:80 $SHA_TAG
+          EOF"
+          rm /tmp/deploy_key