fix(cd): use robust manual kubectl setup to avoid base64 truncated input error

.gitea/workflows/cd-deploy.yml

@@ -45,8 +45,14 @@ jobs:
           kustomize edit set image 192.168.241.13:8080/workclub-frontend=192.168.241.13:8080/workclub-frontend:$IMAGE_TAG
 
       - name: Deploy to Kubernetes
-        uses: https://github.com/steebchen/kubectl@master
+        run: |
+          mkdir -p ~/.kube
+          if echo "${{ secrets.KUBECONFIG }}" | grep -q '^[A-Za-z0-9+/=]*$'; then
+            echo "${{ secrets.KUBECONFIG }}" | base64 -d > ~/.kube/config
+          else
+            echo "${{ secrets.KUBECONFIG }}" > ~/.kube/config
+          fi
+          chmod 600 ~/.kube/config
+          kubectl apply -k infra/k8s/overlays/dev
         env:
-          KUBE_CONFIG_DATA: ${{ secrets.KUBECONFIG }}
-        with:
-          args: apply -k infra/k8s/overlays/dev
+          KUBECONFIG: /home/runner/.kube/config