Add a camera-renderer setting to lab_sim

[danwahl]

[written by AI]

needs: moveit_pro/#22738

Motivation

moveit_pro gains an optional path-traced camera renderer (PickNikRobotics/moveit_pro#22738). Nothing in that repository starts it, by design — a configuration has to ask for it. This wires lab_sim up to ask.

Brief description

One environment variable, MOVEIT_PRO_CAMERA_RENDERER, selects which renderer produces lab_sim's camera topics:

value	cameras
mujoco	MuJoCo only, on <camera>/color. The default, and the only option on an image carrying no Nyx runtime — every arm64 image and the amd64 CPU image.
nyx	Nyx only, on <camera>/nyx_color. MuJoCo's camera and point-cloud rates go to 0.
both	Both, on their own topics, at the cost of running two renderers.

The same variable drives both halves — picknik_ur.xacro resolves the MuJoCo ros2_control rates, runtime.launch.xml decides whether to include the Nyx node — so the description and the launch file cannot disagree about which renderer is running.

Two details worth a reviewer's attention:

• point_cloud_publish_rate follows render_publish_rate rather than standing alone. The cloud timer publishes what the render timer produced (mujoco_system.cpp:1165), so zeroing only the render rate leaves a cloud timer running against a stopped renderer, reporting every camera as never having rendered, forever. Nyx has no depth output, so selecting nyx gives up point clouds — the same reason the new topic is additive rather than a replacement.
• An unrecognized value fails the description instead of quietly leaving the configuration with no cameras at all. The xacro indexes a dict(...) by the value, which raises naming both the bad value and the expression. (A {...} literal cannot be used here: xacro's ${...} scanner stops at the first } and reports '{' was never closed.)

How it was tested

• pre-commit run on both changed files — green. prettier reformats runtime.launch.xml; .xacro is not matched by that hook.
• All three values plus an unrecognized one were run through xacro: mujoco, nyx, and both resolve to the intended rates, and bogus fails with error: 'bogus' naming the value.
• The launch condition syntax ($(eval '"$(var x)" in ("a","b")')) and the nested $(env USER_WS $(env HOME)/user_ws) default were each proved under ROS 2 Jazzy.
• find-pkg-share picknik_nyx_renderer is not yet verified end to end: the package exists in no published image until moveit_pro#22738 merges. That is what the needs: line above is for.

🤖 Generated with Claude Code

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[github-actions]

MoveIt Pro Example WS - Objectives Integration Test Report

• lab_sim
  • ❌ jazzy: no report produced — see run logs
• hangar_sim
  • ❌ jazzy: no report produced — see run logs