feat(ontology): Implement OntologyIngestor and update exports

- Added OntologyIngestor in semantica/ingest/ontology_ingestor.py
- Updated semantica/ontology/__init__.py to export OntologyIngestor
- Updated semantica/ingest/methods.py to use OntologyIngestor
- Added tests for ontology ingestion
- Cleaned up temporary files

examples/demo_ontology_ingest.py

@@ -0,0 +1,68 @@
+import os
+import shutil
+import tempfile
+from pathlib import Path
+from semantica.ingest import ingest, ingest_ontology, OntologyData
+
+def demo_ontology_ingestion():
+    print("=== Ontology Ingestion Demo ===")
+    
+    # Create a sample ontology file
+    sample_ttl = """
+    @prefix : <http://example.org/demo/> .
+    @prefix owl: <http://www.w3.org/2002/07/owl#> .
+    @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+    @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+
+    <http://example.org/demo/> rdf:type owl:Ontology ;
+        rdfs:label "Demo Ontology" ;
+        rdfs:comment "A simple ontology for demonstration." .
+
+    :DemoClass rdf:type owl:Class ;
+        rdfs:label "Demo Class" .
+    """
+    
+    with tempfile.NamedTemporaryFile(delete=False, suffix=".ttl", mode="w") as tmp:
+        tmp.write(sample_ttl)
+        tmp_path = tmp.name
+        
+    print(f"\nCreated temporary ontology file: {tmp_path}")
+    
+    try:
+        # 1. Use ingest_ontology convenience function
+        print("\n--- Method 1: ingest_ontology() ---")
+        result = ingest_ontology(tmp_path)
+        
+        if isinstance(result, OntologyData):
+            print(f"Success! Ingested ontology: {result.data.get('name')}")
+            print(f"Format: {result.metadata.get('format')}")
+            print(f"Classes found: {len(result.data.get('classes', []))}")
+            for cls in result.data.get('classes', []):
+                print(f"  - {cls.get('name')} ({cls.get('uri')})")
+        else:
+            print("Unexpected result type:", type(result))
+
+        # 2. Use unified ingest function
+        print("\n--- Method 2: Unified ingest() ---")
+        # Explicitly setting source_type="ontology" ensures it uses OntologyIngestor
+        unified_result = ingest(tmp_path, source_type="ontology")
+        
+        if "ontology" in unified_result:
+            ont_data = unified_result["ontology"]
+            if isinstance(ont_data, OntologyData):
+                 print(f"Success! Ingested via unified interface.")
+                 print(f"Ontology Name: {ont_data.data.get('name')}")
+            else:
+                 print(f"Got 'ontology' key but value is {type(ont_data)}")
+        else:
+            print("Unified ingest result keys:", unified_result.keys())
+
+    except Exception as e:
+        print(f"An error occurred: {e}")
+    finally:
+        if os.path.exists(tmp_path):
+            os.remove(tmp_path)
+            print(f"\nCleaned up temporary file.")
+
+if __name__ == "__main__":
+    demo_ontology_ingestion()