feat: integrate SimpleCADAPI 2.0.2 CAD workflows

SimpleCADAPI/skills/simplecadapi/references/docs/api/requires_session.md

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+# requires_session
+
+## API Definition
+
+```python
+def requires_session(func=None) -> Callable
+```
+
+*Source: graph.py*
+
+## Import Surface
+
+- top-level: `from simplecadapi import requires_session`
+
+## Description
+
+Decorate a reusable graph-producing builder that must run inside the caller's
+active `GraphSession`. It reuses the session owned by the enclosing `@model`
+function and validates returned graph values against that session.
+
+Calling a `@requires_session` builder without an active session raises
+`RuntimeError`. Builders must not create their own `GraphSession`.