ci: migrate image registry to GHCR (drop :5000 insecure-registry steps)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: BeomSeokYu

.github/workflows/cicd.yml

@@ -53,26 +53,11 @@ jobs:
           fi
           echo "REGISTRY_HOST=${REGISTRY_IMAGE%%/*}" >> $GITHUB_ENV
 
-      - name: Allow insecure registry
-        run: |
-          echo "{\"insecure-registries\":[\"${REGISTRY_HOST}\"]}" | sudo tee /etc/docker/daemon.json
-          sudo systemctl restart docker
-
-      - name: Write Buildx config
-        run: |
-          cat > buildkitd.toml <<EOF
-          [registry."${REGISTRY_HOST}"]
-            http = true
-            insecure = true
-          EOF
-
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
-        with:
-          buildkitd-config: buildkitd.toml
 
       - name: Login to registry
         uses: docker/login-action@v3