ros-humble-ros-workspace ships prefix-level setup scripts that reference _local_setup_util_sh.py, which is never present in a conda prefix

Issue

ros-humble-ros-workspace 1.0.2 installs the following files directly into the conda prefix root:

• local_setup.bash, local_setup.sh, local_setup.zsh
• setup.bash, setup.sh, setup.zsh
• _local_setup_util.py

These scripts mimic the layout that colcon build generates inside install/, but _local_setup_util_sh.py — the shell-specific utility invoked by local_setup.sh — is not included, because it is only generated at build time by colcon, never installed via conda.

When a colcon workspace chains the conda prefix as an underlay (as instructed by the RoboStack Getting Started guide via scripts = ["install/setup.bash"] in pixi.toml), local_setup.sh tries to invoke _local_setup_util_sh.py from within the conda prefix and fails silently — the workspace environment is never properly sourced.

This is the root cause of the silent failure reported in #409. A mitigation (file-existence guard in colcon's prefix.sh.em) has been merged in conda-forge/colcon-core-feedstock#62, but the root fix should be here: either remove the _local_setup_util_sh.py invocation from the scripts shipped by ros-humble-ros-workspace, or remove those prefix-level scripts entirely if they are not needed.

Installed packages (relevant)

Full list available on request (pixi run -e humble conda list).

Environment info

• Platform: macOS Apple Silicon (osx-arm64)
• Pixi: used in place of mamba/conda
• ROS distro: Humble Hawksbill
• Related: #409, conda-forge/colcon-core-feedstock#62

Inspect the ros-humble-ros-workspace packaging and the shipped local_setup.sh, setup.sh, and _local_setup_util.py files; start by reproducing the failure when the conda prefix is chained as a colcon underlay. Determine whether the prefix-level scripts should be corrected or removed, then verify that sourcing the underlay succeeds without invoking the absent _local_setup_util_sh.py.