forked from 1b-agent/opencadstudio-upstream
- SetAttribute op + GetAttributes/GetBlockEntities queries (append-only). - backend set_attribute (add/update Insert attribute), attributes (tag,value pairs), block_entities (read-only traversal via BlockRecord.entity_handles -> id+kind+bounds). - facade Entity::set_attribute/attributes, Document::block_entities. - spec Insert methods; api_reference + binding_schema regenerated; mocks + baseline. - Query enum: drop Copy (GetBlockEntities carries String). - Test phase3_attributes_and_block_traversal -> 608 host lib + 3 consistency green.