feat(nlp-service): scaffold — models, requirements, CLAUDE.md

Task 1: Create standalone FastAPI service scaffold with models, test framework,
and documentation. Includes ParseRequest, ParseResponse Pydantic models matching
OllamaExtraction contract, plus three passing tests validating model validation.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nlp-service/test_extractor.py

@@ -0,0 +1,33 @@
+import pytest
+from pydantic import ValidationError
+
+
+# ── Models ──────────────────────────────────────────────────────────────────
+
+def test_parse_request_valid():
+    from models import ParseRequest
+    req = ParseRequest(query="Briefe von Opa", lang="de")
+    assert req.query == "Briefe von Opa"
+    assert req.lang == "de"
+
+
+def test_parse_request_rejects_unknown_lang():
+    from models import ParseRequest
+    with pytest.raises(ValidationError):
+        ParseRequest(query="Letters from grandpa", lang="fr")
+
+
+def test_parse_response_serializes_nulls():
+    from models import ParseResponse
+    resp = ParseResponse(
+        personNames=["Opa"],
+        personRole="sender",
+        dateFrom=None,
+        dateTo="1920-12-31",
+        keywords=["brief"],
+        rawQuery="Briefe von Opa",
+    )
+    data = resp.model_dump()
+    assert data["dateFrom"] is None
+    assert data["dateTo"] == "1920-12-31"
+    assert data["personRole"] == "sender"