fix(turtlebot3): Fix shellcheck issues

- Remove unused YELLOW variable from check-entities.sh
- Add -r flag to read command in restore-normal.sh to handle backslashes properly

Author: bburda

demos/turtlebot3_integration/check-entities.sh

@@ -8,7 +8,6 @@ API_BASE="${GATEWAY_URL}/api/v1"
 # Colors for output
 BLUE='\033[0;34m'
 GREEN='\033[0;32m'
-YELLOW='\033[1;33m'
 NC='\033[0m'
 
 echo_step() {

demos/turtlebot3_integration/restore-normal.sh

@@ -26,7 +26,7 @@ echo "Canceling any active navigation goals..."
 # List active executions and cancel them
 EXECUTIONS=$(curl -s "${API_BASE}/apps/bt-navigator/operations/navigate_to_pose/executions" 2>/dev/null)
 if echo "$EXECUTIONS" | jq -e '.items[]' > /dev/null 2>&1; then
-    echo "$EXECUTIONS" | jq -r '.items[].id' | while read EXEC_ID; do
+    echo "$EXECUTIONS" | jq -r '.items[].id' | while read -r EXEC_ID; do
         if [ -n "$EXEC_ID" ]; then
             curl -s -X DELETE "${API_BASE}/apps/bt-navigator/operations/navigate_to_pose/executions/$EXEC_ID" > /dev/null 2>&1
             echo "  Canceled execution: $EXEC_ID"