base_x/base_y were only float()-cast, so a NaN base point was written into
the BLOCK record; a primitive on a layer the drawing lacks was written as a
dangling reference doc.audit() never flags (and on COM would fail mid-loop
after Blocks.Add). validate_base_point names the key; the layer table is
probed before the first write and the missing names are refused, or created
and reported as layers_created when create_layers=true (new optional kwarg,
contract + both engines + tool).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
