[codex] add K3s update center (#314)

* add k3s update center

* fix update center status timeouts

* Polish update center settings UI

* Document k3s update center

* Refocus update center docs for users

* Clarify k3s migration path in docs

docker/Dockerfile

@@ -21,6 +21,21 @@ FROM node:22-bookworm-slim
 
 WORKDIR /app
 
+ARG TARGETARCH
+ARG KUBECTL_VERSION=v1.31.8
+ARG HELM_VERSION=v3.18.6
+
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends ca-certificates curl tar gzip \
+  && case "$TARGETARCH" in amd64|arm64) export ARCH="$TARGETARCH" ;; *) echo "Unsupported TARGETARCH: $TARGETARCH" >&2; exit 1 ;; esac \
+  && curl -fsSL -o /usr/local/bin/kubectl "https://dl.k8s.io/release/${KUBECTL_VERSION}/bin/linux/${ARCH}/kubectl" \
+  && chmod +x /usr/local/bin/kubectl \
+  && curl -fsSL "https://get.helm.sh/helm-${HELM_VERSION}-linux-${ARCH}.tar.gz" -o /tmp/helm.tgz \
+  && tar -xzf /tmp/helm.tgz -C /tmp \
+  && mv "/tmp/linux-${ARCH}/helm" /usr/local/bin/helm \
+  && chmod +x /usr/local/bin/helm \
+  && rm -rf /tmp/helm.tgz "/tmp/linux-${ARCH}" /var/lib/apt/lists/*
+
 COPY --from=builder /app/dist ./dist
 COPY --from=builder /app/node_modules ./node_modules
 COPY --from=builder /app/package.json ./