fix: include pnpm in runtime image for openclaw update (vignesh07#72)

Author: vignesh07

Dockerfile

@@ -51,6 +51,9 @@ RUN apt-get update \
     ca-certificates \
   && rm -rf /var/lib/apt/lists/*
 
+# `openclaw update` expects pnpm. Provide it in the runtime image.
+RUN corepack enable && corepack prepare pnpm@10.23.0 --activate
+
 WORKDIR /app
 
 # Wrapper deps