fix: add docker group to gateway container for docker.sock access

docker/Dockerfile.gateway

@@ -32,9 +32,11 @@ RUN apk add --no-cache \
     jq \
     && rm -rf /var/cache/apk/*
 
-# Create non-root user
-RUN addgroup -g 1001 goclaw && \
-    adduser -u 1001 -G goclaw -s /bin/sh -D goclaw
+# Create non-root user and add to docker group (GID 999 — matches host docker group)
+RUN addgroup -g 999 docker 2>/dev/null || true && \
+    addgroup -g 1001 goclaw && \
+    adduser -u 1001 -G goclaw -s /bin/sh -D goclaw && \
+    adduser goclaw docker
 
 WORKDIR /app