feat: Fehler-melden + Datenherkunft auf Kontakte & Würfe erweitern

- Kontakt-Detailseite: „Fehler melden"- und „Datenherkunft"-Button.
- Wurf-Ansicht: „Datenherkunft"-Button (Feedback war bereits vorhanden).
- Feedback-Entity um loses, nullable ContactId erweitert (kein FK → übersteht
  Ingest-Wipe); Migration AddFeedbackContactId.
- Contact.Provenance + Litter.Provenance (nullable text); Migration
  AddContactLitterProvenance; im Ingest gemappt und in den DTOs zurückgegeben.
- Import: build_entity_provenance() generalisiert; Kontakte (sourceFiles,
  Züchter/Abnehmer-Hinweise) und Würfe (Wurfchronik vs. Diagramm-rekonstruiert,
  Geschwister-Merge) erhalten Herkunftsdaten in resolved_import.json.
- Frontend: ProvenanceDialog generalisiert (EntityProvenance + entityLabel).

Tests erweitert (Ingest-Round-trip Kontakt/Wurf, contact-scoped Feedback
übersteht Wipe). dotnet(212)/vitest(129)/playwright(36)/tsc/eslint grün.

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

GerbilManager.Tests/FeedbackEndpointTests.cs

@@ -75,7 +75,7 @@ public class FeedbackEndpointTests : IClassFixture<ApiFactory>
             {
                 Contacts = new[]
                 {
-                    new { Id = contactId, Name = "Test Breeder", Email = "t@e.de", Phone = "", Address = "", Notes = (string?)null, IsBreeder = true, IsReceiver = false }
+                    new { Id = contactId, Name = "Test Breeder", Email = "t@e.de", Phone = "", Address = "", Notes = (string?)null, IsBreeder = true, IsReceiver = false, NameSuffix = (string?)null, Provenance = (string?)null }
                 },
                 Litters = new[]
                 {
@@ -109,6 +109,19 @@ public class FeedbackEndpointTests : IClassFixture<ApiFactory>
                 Url = "http://localhost/rennmaeuse/papa",
                 CreatedAt = DateTimeOffset.UtcNow,
             });
+            // A contact-scoped feedback report — the ContactId is a loose (FK-free) id,
+            // so it must survive the contact-table wipe just like gerbil/litter ids.
+            var contactFeedbackId = Guid.NewGuid();
+            db.Feedback.Add(new Feedback
+            {
+                Id = contactFeedbackId,
+                Message = "Adresse stimmt nicht.",
+                Context = "contact-detail",
+                ContactId = contactId,
+                EntityName = "Test Breeder",
+                Url = "http://localhost/kontakte/test-breeder",
+                CreatedAt = DateTimeOffset.UtcNow,
+            });
             await db.SaveChangesAsync();
 
             var config = new ConfigurationBuilder()
@@ -119,12 +132,18 @@ public class FeedbackEndpointTests : IClassFixture<ApiFactory>
             var result = await new IngestResolvedService(db, config, null!).RunAsync();
             Assert.Contains("Ingestion successful!", result);
 
-            // Gerbils/litters were wiped & re-created, but feedback is untouched.
-            var survivor = await db.Feedback.SingleAsync();
-            Assert.Equal(feedbackId, survivor.Id);
+            // Gerbils/litters/contacts were wiped & re-created, but feedback is untouched.
+            var survivor = await db.Feedback.SingleAsync(f => f.Id == feedbackId);
             Assert.Equal(fatherId, survivor.GerbilId);   // loose id preserved even though the gerbil row was deleted/recreated
             Assert.Equal(litterId, survivor.LitterId);
             Assert.Equal("Papa", survivor.EntityName);
+
+            // The contact-scoped report also survives the contacts wipe (loose ContactId).
+            var contactSurvivor = await db.Feedback.SingleAsync(f => f.Id == contactFeedbackId);
+            Assert.Equal(contactId, contactSurvivor.ContactId);
+            Assert.Equal("contact-detail", contactSurvivor.Context);
+            Assert.Equal("Test Breeder", contactSurvivor.EntityName);
+            Assert.Equal(2, await db.Feedback.CountAsync());
         }
         finally
         {

GerbilManager.Tests/IngestResolvedServiceTests.cs

@@ -36,7 +36,8 @@ namespace GerbilManager.Tests
                         Email = "test@example.com",
                         Homepage = "",
                         Phone = "",
-                        Address = ""
+                        Address = "",
+                        Provenance = (string?)"{\"sourceFiles\":[\"Stammbaum\"],\"mergedRecordCount\":1,\"notes\":[\"als Züchter erkannt\"]}"
                     }
                 },
                 Litters = new[]
@@ -54,7 +55,8 @@ namespace GerbilManager.Tests
                         Notes = "Test litter notes",
                         PairingCode = "PC01",
                         ExternalRef = "ext-litter-1",
-                        LitterLetter = "A"
+                        LitterLetter = "A",
+                        Provenance = (string?)"{\"sourceFiles\":[\"Wurfchronik-Detail.docx\"],\"mergedRecordCount\":1,\"fromWurfchronik\":true,\"notes\":[\"aus Wurfchronik\"]}"
                     }
                 },
                 Gerbils = new[]
@@ -184,6 +186,15 @@ namespace GerbilManager.Tests
             Assert.Contains("Stammbaum von Papa.xlsx", father.Provenance);
             Assert.Contains("mergedRecordCount", father.Provenance);
             Assert.Null(mother.Provenance);
+
+            // Contact + litter provenance also round-trips through the ingest.
+            var contact = await db.Contacts.SingleAsync();
+            Assert.NotNull(contact.Provenance);
+            Assert.Contains("als Züchter erkannt", contact.Provenance);
+
+            Assert.NotNull(litter.Provenance);
+            Assert.Contains("aus Wurfchronik", litter.Provenance);
+            Assert.Contains("fromWurfchronik", litter.Provenance);
         }
     }
 }