feat(import): Abgabeverträge als SaleContract-Datensätze importieren

Die ~1095 geparsten Verträge werden jetzt als echte SaleContract-Records erzeugt,
sodass die Verträge-Seite gefüllt ist (statt 0). enrich_from_contracts() liefert
zusätzlich eine saleContracts-Liste (deterministische Id aus Dateiname, Käufer-
ContactId, Preis, Abgabe-/Vertragsdatum, FileName, gematchte Tier-Ids); main()
schreibt sie als Top-Level-Key in resolved_import.json. IngestResolvedService legt
SaleContract + SaleContractAnimal an (FK-sicher nach Kontakten/Tieren, unbekannte
Links übersprungen) — Tabelle wird wie gehabt gewischt und aus dem Payload neu
befüllt (idempotent).

Ergebnis: 1033 Verträge (611 mit ≥1 Tier, alle datiert; 54 Dateinamen-Dubletten
zusammengefasst, 7 datumlose + 1 ohne Käufer übersprungen). Kein Schema-Change
(datumlose übersprungen statt Spalten nullable → keine Migration).

DOCX-Download: importierte Verträge haben keine Word-Datei im contract-storage →
DTO.HasFile=false, Frontend blendet den Word-Button aus (Hinweis „Keine Word-
Datei"), PDF wird weiterhin generiert. Download-Endpoint liefert sauber 404 statt
500 bei fehlender Datei.

Tests: dotnet 213, vitest 129, playwright 16 (neuer vertraege.spec.ts), Python grün.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tools/import/test_merge_resolve.py

@@ -345,6 +345,75 @@ check("history: discard lines carry the warning marker",
       all(s.startswith(m.DISCARD_MARK) for s in h_disc if "verworfen" in s))
 
 
+# ── enrich_from_contracts: SaleContract record emission ───────────────────────
+# A contract whose buyer resolves to a contact and whose animal call-name matches
+# a breeder-owned gerbil must yield a SaleContract record carrying the buyer
+# ContactId, a deterministic Id, the parsed dates and the matched gerbil id.
+def _balu():
+    # A breeder-owned ("Chaoten") gerbil whose call-name is "Balu".
+    return {
+        "Id": "11111111-1111-1111-1111-111111111111",
+        "Name": "Balu von den kleinen Chaoten",
+        "Gender": "male", "DateOfBirth": "2022-05-01",
+        "OriginBreeder": "Zucht der kleinen Chaoten",
+        "Status": "Active", "ColorVarietyId": None,
+        "Provenance": None,
+    }
+
+_g = _balu()
+_resolved = [_g]
+_contacts_by_norm = {}
+_contracts = [{
+    "sourceFile": "Zucht der kleinen Chaoten _ Schwarz (Balu) - Max Muster_.docx",
+    "buyer": "Max Muster", "animals": ["Balu"], "color": "schwarz",
+    "gender": "Male", "dob": "2022-05-01",
+    "handoverDate": "2022-07-01", "contractDate": "2022-07-01", "price": "30,00",
+}]
+_stats, _sale = m.enrich_from_contracts(_contracts, _resolved, _contacts_by_norm, {})
+check("contracts: exactly one SaleContract record emitted", len(_sale) == 1)
+_rec = _sale[0] if _sale else {}
+check("contracts: record Id is deterministic from filename",
+      _rec.get("Id") == m.generate_guid(
+          "contract-Zucht der kleinen Chaoten _ Schwarz (Balu) - Max Muster_.docx"))
+check("contracts: record ContactId is the resolved buyer contact",
+      _rec.get("ContactId") and
+      _rec["ContactId"] == _contacts_by_norm.get(m.normalize_name("Max Muster"), {}).get("Id"))
+check("contracts: record lists the matched gerbil",
+      _rec.get("Animals") == [_g["Id"]])
+check("contracts: price parsed as float", _rec.get("Price") == 30.0)
+check("contracts: dates carried through",
+      _rec.get("HandoverDate") == "2022-07-01" and _rec.get("ContractDate") == "2022-07-01")
+check("contracts: stats count the created record", _stats.get("records_created") == 1)
+
+# A dateless contract is skipped from record creation (non-nullable DateOnly) but
+# still counted, and the buyer contact is still created.
+_c2 = [{
+    "sourceFile": "Zucht der kleinen Chaoten _ (Nala) - Erika Muster_.docx",
+    "buyer": "Erika Muster", "animals": ["Nala"], "color": "",
+    "gender": "", "dob": "", "handoverDate": "", "contractDate": "", "price": "",
+}]
+_stats2, _sale2 = m.enrich_from_contracts(_c2, [], {}, {})
+check("contracts: dateless contract skipped from records", len(_sale2) == 0)
+check("contracts: dateless contract counted", _stats2.get("dateless_skipped") == 1)
+
+# Price-only / no-date fallback: contract with only a contractDate gets it copied
+# into HandoverDate too (and vice versa), and an animal-less contract still
+# becomes a record (better to show it than drop it).
+_c3 = [{
+    "sourceFile": "Zucht der kleinen Chaoten _ (Unbekannt) - Tom Muster_.docx",
+    "buyer": "Tom Muster", "animals": ["Unbekannt"], "color": "",
+    "gender": "", "dob": "", "handoverDate": "", "contractDate": "2023-01-15",
+    "price": "",
+}]
+_stats3, _sale3 = m.enrich_from_contracts(_c3, [], {}, {})
+check("contracts: animal-less contract still becomes a record", len(_sale3) == 1)
+check("contracts: missing handover falls back to contract date",
+      _sale3 and _sale3[0]["HandoverDate"] == "2023-01-15"
+      and _sale3[0]["ContractDate"] == "2023-01-15")
+check("contracts: animal-less record has empty Animals list",
+      _sale3 and _sale3[0]["Animals"] == [])
+
+
 if check.failed:
     print(f"\n{check.failed} test(s) FAILED")
     sys.exit(1)