refactor: add DesignIR distillation pipeline

text-to-cad/CONTRIBUTING.md

@@ -39,7 +39,6 @@ When running a tool manually, use that skill's interpreter:
 
 ```bash
 .venv/skills/cad/bin/python skills/cad/scripts/step --help
-.venv/skills/urdf/bin/python skills/urdf/scripts/urdf --help
 ```
 
 ## Link Skills Into Your Agent
@@ -307,12 +306,8 @@ Use `AGENTS.md` or `scripts/README.md` for path-specific validation when you are
 working in a particular package, skill, plugin, docs site, or production-output
 path.
 
-For targeted Python skill-script tests, run the relevant unittest files with the
-repo-local Python runtime, for example:
-
-```bash
-./.venv/bin/python -m unittest tests/python/skills/urdf/test_cli.py
-```
+For targeted Python skill-script tests, run the relevant unittest files with
+the repo-local Python runtime.
 
 Python tests live under `tests/python/`, grouped by tested surface:
 `skills/<skill>`, `packages/<package>`, `viewer/<service>`, and `global`.