[T-K-233]

Rewrites the README for users of the description, moves the maintainer details to docs/, and fixes the problems that a review of the repository found.

Docs

• README: 170 → 108 lines. It has an image of each variant (visual meshes and colliders), the variants table, the use from Python and ROS 2, a static viewer script, the conventions and the design notes.
• Design notes: the geometry is for simulation, and the CAD serves renders. Each variant has one collider set, and a biped consumer selects colliders by name at load time. The URDF cylinders are shorter than the MJCF capsules: the left_knee_pitch collider is 0.304 m against 0.392 m. Isaac Lab 3.0 removed replace_cylinders_with_capsules, so the docs give no workaround.
• docs/: colliders.md, ros2_control.md and generation.md hold the old README sections, the xacro args, the differences between the backends, the contact model, the collider editing steps and an mjlab feet-only CollisionCfg example.
• Images: python -m lite_description.workflow.render_images renders docs/images/ through a new docs dependency group. The published package gets no new command and no Pillow.
• Install URL: berkeley-humanoids/lite_description. The old URL works only through the GitHub redirect.

Fixes

• Delete two lite meshes that no model references, and clear meshes/visual/ on export. The mesh test now checks both directions.
• package.xml 0.0.2 → 0.5.0, to match pyproject.toml. A test checks the match.
• lite and lite_pro MJCF: implicitfast instead of the default Euler, as the MuJoCo docs recommend and the other variants use.
• Delete 26 scad files that add no collider. The generated models do not change.
• Biped scene floors: drop condim and friction, which were the MuJoCo defaults. mjlab trains on a plane with no contact attributes, so the floor now reads as the training plane. The compiled contacts do not change.
• patch_contacts docstring: condim 1 makes only leg-leg contacts frictionless. A leg on the ground has friction, as in mjlab training.

Breaking: the old README anchors #usage, #hardware-backends, #re-generating-from-cad and #tests are gone.

The _comment in lite_biped/cad/ros2_control.json still says that mock hardware has the IMU block. The docs follow the generated xacro, which has no IMU block for mock hardware.

Verification

• The Python snippets of the README and docs/colliders.md run. The viewer script opens the model.
• The render script reproduces the committed images byte for byte.
• uv run --group test pytest passes at each commit: 108 passed, 32 skipped (the xacro tests).
• Each remaining scad file adds a collider, and each URDF collider has a scad source. OpenSCAD checked this.
• Not run: the ROS 2 xacro command. A reviewer ran the mjlab example with mjlab 1.6.0.

🤖 Generated with Claude Code

https://claude.ai/code/session_01FtY7D2vUc6McSBa1Kqq394