chore: import upstream snapshot with attribution

examples/5_docker_turtlesim/scripts/launch_linux.sh

@@ -0,0 +1,42 @@
+#!/bin/bash
+# Linux startup script for turtlesim GUI
+
+set -e
+
+echo "Starting Turtlesim on Linux with GUI"
+echo "========================================"
+
+# Step 1: Check if X11 is available
+if [[ -z "$DISPLAY" ]]; then
+    echo "ERROR: DISPLAY variable not set"
+    echo "X11 forwarding is required. Are you running in a GUI environment?"
+    exit 1
+fi
+
+echo "Using DISPLAY: $DISPLAY"
+
+# Step 2: Allow Docker to access X11
+if command -v xhost >/dev/null 2>&1; then
+    echo "Allowing Docker X11 access..."
+    xhost +local:docker >/dev/null 2>&1 || {
+        echo "WARNING: xhost command failed, trying without sudo..."
+        xhost + >/dev/null 2>&1 || echo "WARNING: Could not run xhost, X11 forwarding may not work"
+    }
+else
+    echo "WARNING: xhost not found. Install with: sudo apt-get install x11-xserver-utils"
+    exit 1
+fi
+
+# Step 3: Export DISPLAY for Docker
+echo "Docker will use DISPLAY=$DISPLAY"
+
+# Step 4: Start the container
+echo ""
+echo "Starting Turtlesim container..."
+echo "If successful, you should see a window with a turtle!"
+echo ""
+
+docker compose up turtlesim
+
+echo ""
+echo "Done! The turtle window should be visible on your screen."