fix ROS2 Jazzy CI: force sequential package builds

The parallel-workers: 1 setting ensures cloudini_lib fully installs
before cloudini_ros starts configuring.

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: facontidavide

.github/workflows/ros-jazzy.yaml

@@ -35,3 +35,9 @@ jobs:
             cloudini_lib
             cloudini_ros
           target-ros2-distro: jazzy
+          colcon-defaults: |
+            {
+              "build": {
+                "parallel-workers": 1
+              }
+            }