Add build-essential package to Dockerfile and update version in config.yaml to 0.5.28

openclaw_assistant/Dockerfile

@@ -5,6 +5,7 @@ FROM ${BUILD_FROM}
 # that occur on Alpine (e.g. clipboard, node-llama-cpp).
 
 # Install base packages (without nodejs/npm - we'll get Node 22 from NodeSource)
+# build-essential provides gcc/cc needed by Homebrew for OpenClaw's brew-managed dependencies
 RUN apt-get update && apt-get install -y --no-install-recommends \
     bash \
     git \
@@ -19,6 +20,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     python3 \
     nginx \
     gnupg \
+    build-essential \
  && apt-get clean \
  && rm -rf /var/lib/apt/lists/*