feat(search): add DocumentSearchResult.withMatchData() factory with match overlay map

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

backend/src/test/java/org/raddatz/familienarchiv/dto/DocumentSearchResultTest.java

@@ -0,0 +1,53 @@
+package org.raddatz.familienarchiv.dto;
+
+import org.junit.jupiter.api.Test;
+import org.raddatz.familienarchiv.model.Document;
+import org.raddatz.familienarchiv.model.DocumentStatus;
+
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class DocumentSearchResultTest {
+
+    private Document doc(UUID id) {
+        return Document.builder()
+                .id(id)
+                .title("Test")
+                .originalFilename("test.pdf")
+                .status(DocumentStatus.UPLOADED)
+                .build();
+    }
+
+    @Test
+    void withMatchData_total_equals_list_size() {
+        UUID id = UUID.randomUUID();
+        List<Document> docs = List.of(doc(id));
+        Map<UUID, SearchMatchData> matchData = Map.of(id, SearchMatchData.empty());
+
+        DocumentSearchResult result = DocumentSearchResult.withMatchData(docs, matchData);
+
+        assertThat(result.total()).isEqualTo(1L);
+    }
+
+    @Test
+    void withMatchData_exposes_match_data_map() {
+        UUID id = UUID.randomUUID();
+        SearchMatchData data = new SearchMatchData("snippet", List.of(), false, List.of(), List.of());
+        DocumentSearchResult result = DocumentSearchResult.withMatchData(List.of(doc(id)), Map.of(id, data));
+
+        assertThat(result.matchData()).containsKey(id);
+        assertThat(result.matchData().get(id).transcriptionSnippet()).isEqualTo("snippet");
+    }
+
+    @Test
+    void of_factory_returns_empty_match_data() {
+        UUID id = UUID.randomUUID();
+        DocumentSearchResult result = DocumentSearchResult.of(List.of(doc(id)));
+
+        assertThat(result.matchData()).isEmpty();
+        assertThat(result.total()).isEqualTo(1L);
+    }
+}