修改agent流程，分步构建cdsl

backend/engine/cdsl_engine/build123d_adapter.py

@@ -306,9 +306,14 @@ class Build123dGeometryAdapter:
     @staticmethod
     def body_geometry(body: Any) -> dict[str, Any]:
         bbox = body.bounding_box()
+        # A feature history can contain several body IDs while still ending in
+        # one connected solid (for example, a base extrusion followed by hole
+        # cuts). Count the current OCC result, never feature history entries.
+        solids = list(body.solids()) if hasattr(body, "solids") else [body]
         return {
             "bbox_mm": [bbox.min.X, bbox.min.Y, bbox.min.Z, bbox.max.X, bbox.max.Y, bbox.max.Z],
             "volume_mm3": float(body.volume),
+            "solid_count": len(solids),
         }
 
     @staticmethod