Add bitbots cargo

[Flova]

Summary

Add a way of integrating cargo with colcon.

Proposed changes

As a demonstration the extrinsic calibration node and the global planning library are build using this way. This should also fix the issue @ayin21 had on her laptop.

Related issues

Checklist

• Run pixi run build
• Write documentation
• Test on your machine
• Test on the robot
• Create issues for future work
• Triage this PR and label it

[MegaIng]

This doesn't build for me; It appears that a global llvm and/or clang version is being found instead which is missing some symbols.

[jaagut]

Apparently:
r2r generates Rust bindings from the ROS C headers on the target machine. On the robot, bindgen is producing rosidl_message_type_support_t as opaque (_address) instead of exposing .data.
I fixed it by vendoring a tiny patched r2r_msg_gen 0.9.5 and overriding it in Cargo.toml. The patch reads the ROS type-support data pointer via the stable C struct prefix instead of relying on bindgen exposing that field. Cargo.lock now resolves r2r_msg_gen to the local patch under patches/r2r_msg_gen-0.9.5.

[jaagut]

I don't like the vendoring solution in the latest commit. Feel free to revert this.

[Flova]

Do we know why the robot is different in this regard?

[ayin21]

Apparently: r2r generates Rust bindings from the ROS C headers on the target machine. On the robot, bindgen is producing rosidl_message_type_support_t as opaque (_address) instead of exposing .data. I fixed it by vendoring a tiny patched r2r_msg_gen 0.9.5 and overriding it in Cargo.toml. The patch reads the ROS type-support data pointer via the stable C struct prefix instead of relying on bindgen exposing that field. Cargo.lock now resolves r2r_msg_gen to the local patch under patches/r2r_msg_gen-0.9.5.

I could reproduce this under a ubuntu 26.04 desktop