[Proposal] Support VisACD convex decomposition in the next DexSim release

[yuecideng]

Proposal

Adapt EmbodiChain to the next DexSim release that includes VIsaCD as a convex decomposition algorithm.

EmbodiChain should expose visacd through its mesh convex-decomposition configuration and forward it correctly to DexSim, alongside the existing coacd and vhacd options.

Suggested scope:

• Update the dexsim_engine dependency to the next release containing VIsaCD support.
• Accept and forward acd_method="visacd" wherever EmbodiChain configures DexSim mesh convex decomposition, including MeshCfg and backward-compatible rigid-object configuration paths.
• Review whether the standalone URDF convex-decomposition toolkit should expose the same method.
• Add tests covering configuration propagation and a representative mesh-loading/decomposition path.
• Update public API documentation and examples that currently list only CoACD and VHACD.

Motivation

DexSim now supports VIsaCD, but EmbodiChain is currently pinned to dexsim_engine==0.4.3 and documents only coacd and vhacd for acd_method. Tracking the integration against the next DexSim release ensures users can select VIsaCD through EmbodiChain without bypassing its configuration APIs.

Additional context

Relevant EmbodiChain areas include:

• pyproject.toml for the DexSim version pin
• embodichain/lab/sim/shapes.py and embodichain/lab/sim/cfg.py for mesh ACD configuration
• embodichain/toolkits/acd/ for the standalone URDF convex-decomposition workflow
• Simulation asset documentation describing supported convex-decomposition methods

Acceptance criteria:

• EmbodiChain depends on a released DexSim version that contains VIsaCD support.
• acd_method="visacd" is accepted and forwarded to DexSim.
• Existing coacd and vhacd behavior remains compatible.
• Automated tests cover the new option.
• User-facing documentation lists VIsaCD and any relevant constraints.

Checklist

• I have checked that there is no similar issue in the repo (required)