Use upstream lidar code

lidar/Dockerfile

@@ -5,14 +5,18 @@ FROM ros:kilted AS builder
 
 SHELL ["/bin/bash", "-c"]
 
+# Pin to a specific branch or tag; override with --build-arg SLLIDAR_REF=<ref>
+ARG SLLIDAR_REF=main
+
 RUN apt-get update && apt-get install -y --no-install-recommends \
+    git \
     python3-colcon-common-extensions \
     && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /ws
 
-# Source is managed as a git subtree — copy directly from the workspace
-COPY lidar/sllidar_ros2/ src/sllidar_ros2/
+RUN git clone --depth 1 --branch ${SLLIDAR_REF} \
+    https://github.com/Slamtec/sllidar_ros2.git src/sllidar_ros2
 
 RUN source /opt/ros/${ROS_DISTRO}/setup.bash && \
     colcon build --packages-select sllidar_ros2