Regenerate merged schema and artifacts to sync with Croissant RAI changes

- Regenerate data_sheets_schema_all.yaml with all module imports merged
- Update Python datamodel with new Croissant RAI classes
- Regenerate JSON-LD and OWL artifacts
- Fixes out-of-sync issue (source was 8 days newer than merged schema)

Changes include:
- 6 new Croissant RAI classes (MissingDataDocumentation, RawDataSource,
  ImputationProtocol, AnnotationAnalysis, MachineAnnotationTools)
- exact_mappings to 20 Croissant RAI properties
- Multivalued attribute fixes

Generated via: make regen-all
Verified via: make check-sync

Author: realmarcin

project/jsonld/data_sheets_schema.jsonld

@@ -9595,9 +9595,9 @@
   ],
   "metamodel_version": "1.7.0",
   "source_file": "data_sheets_schema.yaml",
-  "source_file_date": "2025-12-18T22:11:52",
+  "source_file_date": "2025-12-18T23:38:21",
   "source_file_size": 15161,
-  "generation_date": "2025-12-18T22:19:33",
+  "generation_date": "2025-12-19T17:05:52",
   "@type": "SchemaDefinition",
   "@context": [
     "project/jsonld/data_sheets_schema.context.jsonld",