Add lider ROS node and move robot control into its own directory

lidar/Dockerfile

@@ -0,0 +1,40 @@
+# syntax=docker/dockerfile:1
+
+# ── Stage 1: build ────────────────────────────────────────────────────────────
+FROM ros:kilted AS builder
+
+SHELL ["/bin/bash", "-c"]
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    python3-colcon-common-extensions \
+    git \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /ws
+
+RUN git clone --depth 1 https://github.com/slamtec/sllidar_ros2.git src/sllidar_ros2
+
+RUN source /opt/ros/${ROS_DISTRO}/setup.bash && \
+    colcon build --packages-select sllidar_ros2
+
+# ── Stage 2: runtime ──────────────────────────────────────────────────────────
+FROM ros:kilted-ros-core
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    ros-${ROS_DISTRO}-rclcpp \
+    ros-${ROS_DISTRO}-sensor-msgs \
+    ros-${ROS_DISTRO}-std-srvs \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY --from=builder /ws/install /ws/install
+
+# Source both ROS base and the workspace overlay on every shell/exec
+RUN echo "source /opt/ros/${ROS_DISTRO}/setup.bash" >> /etc/bash.bashrc && \
+    echo "source /ws/install/setup.bash"             >> /etc/bash.bashrc
+
+# Reuse the same entrypoint as the robot container (sources overlays, starts daemon)
+COPY docker-entrypoint.sh /docker-entrypoint.sh
+RUN chmod +x /docker-entrypoint.sh
+
+ENTRYPOINT ["/docker-entrypoint.sh"]
+CMD ["ros2", "launch", "sllidar_ros2", "sllidar_a1_launch.py"]