test(importing): pin relationship error propagation and short-row reads

Add a negative test that an unexpected DomainException from
addRelationshipIdempotently propagates rather than being swallowed (only
DUPLICATE/CIRCULAR are caught for idempotency), guarding against a future
swallow-all refactor. Add a CanonicalSheetReader test for a row narrower than
the header (POI omits trailing empty cells) reading absent columns as "".

Refs #669

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/src/test/java/org/raddatz/familienarchiv/importing/CanonicalSheetReaderTest.java

@@ -55,6 +55,21 @@ class CanonicalSheetReaderTest {
         assertThat(rows.get(0).get("does_not_exist")).isEmpty();
     }
 
+    @Test
+    void get_returnsEmptyString_forTrailingColumns_whenRowShorterThanHeader(@TempDir Path tempDir) throws Exception {
+        // POI omits trailing empty cells, so a real-world artifact row can be narrower than
+        // the header. The missing columns must read as "" rather than throwing.
+        Path xlsx = write(tempDir,
+                List.of("index", "file", "summary"),
+                List.of(List.of("W-0001")));
+
+        List<CanonicalSheetReader.Row> rows = CanonicalSheetReader.readRows(xlsx.toFile(), List.of("index", "file", "summary"));
+
+        assertThat(rows.get(0).get("index")).isEqualTo("W-0001");
+        assertThat(rows.get(0).get("file")).isEmpty();
+        assertThat(rows.get(0).get("summary")).isEmpty();
+    }
+
     @Test
     void splitList_splitsOnPipe() {
         assertThat(CanonicalSheetReader.splitList("a|b|c")).containsExactly("a", "b", "c");

backend/src/test/java/org/raddatz/familienarchiv/importing/PersonTreeImporterTest.java

@@ -19,6 +19,7 @@ import java.nio.file.Path;
 import java.util.UUID;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.doThrow;
@@ -106,6 +107,31 @@ class PersonTreeImporterTest {
         verify(relationshipService).addRelationship(any(), any());
     }
 
+    @Test
+    void load_propagatesUnexpectedDomainException_fromAddRelationship(@TempDir Path tempDir) throws Exception {
+        PersonService personService = mock(PersonService.class);
+        RelationshipService relationshipService = mock(RelationshipService.class);
+        when(personService.upsertBySourceRef(any()))
+                .thenAnswer(inv -> personOf(inv.getArgument(0)));
+        // An unexpected ErrorCode (not DUPLICATE/CIRCULAR) must NOT be swallowed.
+        doThrow(DomainException.internal(ErrorCode.INTERNAL_ERROR, "boom"))
+                .when(relationshipService).addRelationship(any(), any());
+        Path json = write(tempDir, """
+                {"persons":[
+                  {"rowId":"row_a","lastName":"A","familyMember":true,"personId":"a"},
+                  {"rowId":"row_b","lastName":"B","familyMember":true,"personId":"b"}
+                ],"relationships":[
+                  {"personId":"row_a","relatedPersonId":"row_b","type":"SPOUSE_OF","source":"verheiratet_mit"}
+                ]}
+                """);
+
+        PersonTreeImporter importer = new PersonTreeImporter(personService, relationshipService);
+
+        assertThatThrownBy(() -> importer.load(json.toFile()))
+                .isInstanceOf(DomainException.class)
+                .extracting("code").isEqualTo(ErrorCode.INTERNAL_ERROR);
+    }
+
     @Test
     void load_skipsRelationship_whenRowIdUnresolved(@TempDir Path tempDir) throws Exception {
         PersonService personService = mock(PersonService.class);