test(document): add LazyInit guard + detail regression tests; prune Document.list graph

Remove trainingLabels from Document.list entity graph now that DocumentListItem
does not touch that association. Integration tests guard against future
LazyInitializationException regressions and confirm Document.full still
loads trainingLabels for the detail endpoint.

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

backend/src/main/java/org/raddatz/familienarchiv/document/Document.java

@@ -31,8 +31,7 @@ import java.util.UUID;
 @NamedEntityGraph(name = "Document.list", attributeNodes = {
         @NamedAttributeNode("sender"),
         @NamedAttributeNode("receivers"),
-        @NamedAttributeNode("tags"),
-        @NamedAttributeNode("trainingLabels")
+        @NamedAttributeNode("tags")
 })
 @Entity
 @Table(name = "documents")

backend/src/test/java/org/raddatz/familienarchiv/document/DocumentListItemIntegrationTest.java

@@ -0,0 +1,98 @@
+package org.raddatz.familienarchiv.document;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import org.raddatz.familienarchiv.PostgresContainerConfig;
+import org.raddatz.familienarchiv.audit.AuditLogQueryService;
+import org.raddatz.familienarchiv.ocr.TrainingLabel;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.Import;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.test.context.ActiveProfiles;
+import org.springframework.test.context.bean.override.mockito.MockitoBean;
+import software.amazon.awssdk.services.s3.S3Client;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
+
+/**
+ * AC #2: Document with trainingLabels does not cause LazyInitializationException in search.
+ * AC #3: Detail API still returns trainingLabels after the Document.list graph change.
+ */
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.NONE)
+@ActiveProfiles("test")
+@Import(PostgresContainerConfig.class)
+class DocumentListItemIntegrationTest {
+
+    @MockitoBean
+    S3Client s3Client;
+
+    @MockitoBean
+    AuditLogQueryService auditLogQueryService;
+
+    @Autowired
+    DocumentRepository documentRepository;
+
+    @Autowired
+    DocumentService documentService;
+
+    @AfterEach
+    void cleanup() {
+        documentRepository.deleteAll();
+    }
+
+    @Test
+    void search_doesNotThrow_whenDocumentHasTrainingLabels() {
+        documentRepository.save(Document.builder()
+                .title("Kurrent Brief")
+                .originalFilename("kurrent.pdf")
+                .status(DocumentStatus.UPLOADED)
+                .trainingLabels(new HashSet<>(Set.of(TrainingLabel.KURRENT_RECOGNITION)))
+                .build());
+
+        assertThatCode(() -> documentService.searchDocuments(
+                null, null, null, null, null, null, null, null,
+                DocumentSort.DATE, "DESC", null,
+                PageRequest.of(0, 50)))
+            .doesNotThrowAnyException();
+    }
+
+    @Test
+    void search_returns_list_item_without_sensitive_fields_when_document_has_training_labels() {
+        documentRepository.save(Document.builder()
+                .title("Kurrent Brief")
+                .originalFilename("kurrent2.pdf")
+                .status(DocumentStatus.UPLOADED)
+                .trainingLabels(new HashSet<>(Set.of(TrainingLabel.KURRENT_RECOGNITION)))
+                .build());
+
+        DocumentSearchResult result = documentService.searchDocuments(
+                null, null, null, null, null, null, null, null,
+                DocumentSort.DATE, "DESC", null,
+                PageRequest.of(0, 50));
+
+        assertThat(result.totalElements()).isGreaterThan(0);
+        DocumentListItem item = result.items().get(0);
+        assertThat(item.id()).isNotNull();
+        assertThat(item.title()).isEqualTo("Kurrent Brief");
+    }
+
+    @Test
+    void detail_stillReturnsTrainingLabels() {
+        Document saved = documentRepository.save(Document.builder()
+                .title("Detail Test")
+                .originalFilename("detail_test.pdf")
+                .status(DocumentStatus.UPLOADED)
+                .trainingLabels(new HashSet<>(Set.of(TrainingLabel.KURRENT_RECOGNITION)))
+                .build());
+
+        // Document.full entity graph (used by findById) must still load trainingLabels
+        Document loaded = documentRepository.findById(saved.getId()).orElseThrow();
+
+        assertThat(loaded.getTrainingLabels()).containsExactly(TrainingLabel.KURRENT_RECOGNITION);
+    }
+}