Skip ROS-dependent integration tests when ROS backend unavailable

[Copilot]

Integration tests requiring ROS backend were failing in regular CI builds due to attempting connections to non-existent ROS servers, causing timeouts with roslibpy.core.RosTimeoutError.

Changes

• .github/workflows/integration.yml: Set COMPAS_FAB_INTEGRATION_TESTS=1 environment variable
• docs/examples/conftest.py: Skip 10 ROS-dependent example files (e.g., 03_forward_kinematics.py, 04_plan_motion.py, 05_collision_objects.py) unless environment variable present
• CHANGELOG.md: Document fix

Behavior

Regular builds (no ROS):

# These files now skip automatically:
# - files/03_forward_kinematics.py
# - files/04_plan_cartesian_motion.py
# - files/05_add_collision_mesh.py
# ... and 7 others

Integration builds (ROS via Docker):

COMPAS_FAB_INTEGRATION_TESTS=1 pytest docs  # All tests run

Files requiring ROS consistently use with RosClient() as client: pattern which fails immediately without backend availability.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Investigate why integration tests fail on CI (but work locally)</issue_title> <issue_description>The integration tests are failing when running on CI, but it's unclear why because they work locally. The branch in which this occurs is the LTS one: LTS-main-1.x.

The log output is the following:

============================= test session starts ==============================
platform linux -- Python 3.11.14, pytest-8.4.2, pluggy-1.6.0
rootdir: /home/runner/work/compas_fab/compas_fab
configfile: pyproject.toml
testpaths: src, tests
plugins: cov-7.0.0, mock-3.15.1
collected 151 items

src/compas_fab/backends/pybullet/client.py .                             [  0%]
src/compas_fab/backends/pybullet/utils.py s                              [  1%]
src/compas_fab/backends/ros/client.py ...                                [  3%]
src/compas_fab/backends/ros/messages/geometry_msgs.py ..                 [  4%]
src/compas_fab/robots/constraints.py .........                           [ 10%]
src/compas_fab/robots/inertia.py .                                       [ 11%]
src/compas_fab/robots/planning_scene.py ........                         [ 16%]
src/compas_fab/robots/reachability_map/vector_generators.py ..           [ 17%]
src/compas_fab/robots/robot.py .......................s....              [ 36%]
src/compas_fab/robots/tool.py ...                                        [ 38%]
src/compas_fab/robots/ur5.py .                                           [ 39%]
src/compas_fab/robots/wrench.py ......                                   [ 43%]
src/compas_fab/sensors/base.py s                                         [ 43%]
src/compas_fab/sensors/baumer.py ss                                      [ 45%]
tests/api/test_api_completeness.py .                                     [ 45%]
tests/api/test_api_stability.py .                                        [ 46%]
tests/backends/kinematics/test_inverse_kinematics.py ......              [ 50%]
tests/backends/kinematics/test_kinematics.py .                           [ 50%]
tests/backends/ros/messages/test_std_msgs.py ............                [ 58%]
tests/backends/ros/test_local_cache_info.py ..                           [ 60%]
tests/backends/test_tasks.py ..                                          [ 61%]
tests/robots/test_duration.py ........                                   [ 66%]
tests/robots/test_reachability.py ..                                     [ 68%]
tests/robots/test_robot.py ......................................        [ 93%]
tests/robots/test_semantics.py .....                                     [ 96%]
tests/robots/test_trajectory.py ....                                     [ 99%]
tests/robots/test_wrench.py .                                            [100%]

=========================== short test summary info ============================
SKIPPED [5] ../../../../../opt/hostedtoolcache/Python/3.11.14/x64/lib/python3.11/site-packages/_pytest/doctest.py:458: all tests skipped by +SKIP option
======================= 146 passed, 5 skipped in 12.44s ========================
============================= test session starts ==============================
platform linux -- Python 3.11.14, pytest-8.4.2, pluggy-1.6.0
rootdir: /home/runner/work/compas_fab/compas_fab
configfile: pyproject.toml
plugins: cov-7.0.0, mock-3.15.1
collected 66 items

docs/examples/01_fundamentals/01_frame_and_transformation.rst ...        [  4%]
docs/examples/01_fundamentals/02_coordinate_frames.rst .                 [  6%]
docs/examples/02_description_models/01_kinematic_model.rst .             [  7%]
docs/examples/02_description_models/02_robot.rst ....                    [ 13%]
docs/examples/03_backends_ros/01_ros_examples.rst ..                     [ 16%]
docs/examples/03_backends_ros/02_robot_models.rst ..                     [ 19%]
docs/examples/03_backends_ros/03_forward_and_inverse_kinematics.rst .FFF [ 25%]
                                                                         [ 25%]
docs/examples/03_backends_ros/04_plan_motion.rst FF                      [ 28%]
docs/examples/03_backends_ros/05_collision_objects.rst FFF               [ 33%]
docs/examples/03_backends_ros/09_ros_create_urdf_ur10_on_tower.rst .     [ 34%]
docs/examples/05_backends_pybullet/01_pybullet_examples.rst ...          [ 39%]
docs/examples/05_backends_pybullet/02_forward_and_inverse_kinematics.rst . [ 40%]
..                                                                       [ 43%]
docs/examples/06_backends_kinematics/01_ik_and_cartesian.rst ...         [ 48%]
docs/examples/07_reachability_map/01_reachability_map.rst ........s      [ 62%]
docs/examples/07_reachability_map/02_vector_generators.rst ............. [ 81%]
.                                                                        [ 83%]
docs/examples/07_reachability_map/03_rp_2D.rst ..........s               [100%]

=================================== FAILURES ====...

</details>

- Fixes compas-dev/compas_fab#454

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