feat(importing): build honest precision-aware document import titles

Wires DocumentTitleFormatter into DocumentImporter.buildDocument: the title
now reads "{index} – {honest date label} – {location}", so a MONTH-precision
letter's title says "Juni 1916" instead of a fabricated "1. Juni 1916", and an
UNKNOWN-date row keeps a bare index title. buildTitle stays under 20 lines by
delegating to the shared formatter (single source of truth with the UI label).

Restores the date+location title behavior that the old MassImportService had
(it appended a full GERMAN_DATE day) but now at the honest precision.

Refs #666

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

backend/src/main/java/org/raddatz/familienarchiv/importing/DocumentImporter.java

@@ -159,7 +159,13 @@ public class DocumentImporter {
         Person sender = resolveSender(row.get("sender_person_id"), senderName);
         Set<Person> receivers = resolveReceivers(row.get("receiver_person_ids"));
 
-        doc.setTitle(index);
+        LocalDate date = parseIsoDate(row.get("date_iso"));
+        DatePrecision precision = parsePrecision(row.get("date_precision"));
+        LocalDate dateEnd = parseIsoDate(row.get("date_end"));
+        String dateRaw = blankToNull(row.get("date_raw"));
+        String location = blankToNull(row.get("location"));
+
+        doc.setTitle(buildTitle(index, date, precision, dateEnd, dateRaw, location));
         doc.setStatus(status);
         doc.setFilePath(s3Key);
         doc.setContentType(contentType);
@@ -171,17 +177,31 @@ public class DocumentImporter {
         doc.getReceivers().clear();
         doc.getReceivers().addAll(receivers);
         doc.setReceiverText(blankToNull(receiverNames));
-        doc.setDocumentDate(parseIsoDate(row.get("date_iso")));
+        doc.setDocumentDate(date);
-        doc.setMetaDatePrecision(parsePrecision(row.get("date_precision")));
+        doc.setMetaDatePrecision(precision);
-        doc.setMetaDateEnd(parseIsoDate(row.get("date_end")));
+        doc.setMetaDateEnd(dateEnd);
-        doc.setMetaDateRaw(blankToNull(row.get("date_raw")));
+        doc.setMetaDateRaw(dateRaw);
-        doc.setLocation(blankToNull(row.get("location")));
+        doc.setLocation(location);
         doc.setSummary(blankToNull(row.get("summary")));
         attachTag(doc, row.get("tags"));
         doc.setMetadataComplete(doc.getDocumentDate() != null || sender != null || !receivers.isEmpty());
         return doc;
     }
 
+    // The title carries the date at the HONEST precision (never a fabricated day) via the
+    // shared DocumentTitleFormatter, plus the location — kept under 20 lines by delegating.
+    private static String buildTitle(String index, LocalDate date, DatePrecision precision,
+                                     LocalDate end, String raw, String location) {
+        StringBuilder title = new StringBuilder(index);
+        if (date != null && precision != DatePrecision.UNKNOWN) {
+            title.append(" – ").append(DocumentTitleFormatter.formatTitleDate(date, precision, end, raw));
+        }
+        if (location != null && !location.isBlank()) {
+            title.append(" – ").append(location);
+        }
+        return title.toString();
+    }
+
     // ─── attribution routing — register-first, always retain raw ─────────────────────
 
     private Person resolveSender(String slug, String rawName) {

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

@@ -404,6 +404,50 @@ class DocumentImporterTest {
                 d.getReceivers().isEmpty() && d.getTags().isEmpty()));
     }
 
+    // ─── title carries the honest date label — never a precision the data lacks ───────
+
+    @Test
+    void load_buildsTitleWithMonthLabel_whenPrecisionIsMonth(@TempDir Path tempDir) throws Exception {
+        ReflectionTestUtils.setField(importer, "importDir", tempDir.toString());
+        when(documentService.findByOriginalFilename("W-0100")).thenReturn(Optional.empty());
+        when(documentService.save(any())).thenAnswer(inv -> inv.getArgument(0));
+        Path xlsx = writeDocs(tempDir, docRow("W-0100", "", "", "", "", "",
+                "1916-06-01", "Juni 1916", "MONTH", ""));
+
+        importer.load(xlsx.toFile());
+
+        verify(documentService).save(org.mockito.ArgumentMatchers.argThat(d ->
+                d.getTitle().contains("Juni 1916") && !d.getTitle().contains("1. Juni")));
+    }
+
+    @Test
+    void load_buildsTitleWithFullDate_whenPrecisionIsDay(@TempDir Path tempDir) throws Exception {
+        ReflectionTestUtils.setField(importer, "importDir", tempDir.toString());
+        when(documentService.findByOriginalFilename("W-0101")).thenReturn(Optional.empty());
+        when(documentService.save(any())).thenAnswer(inv -> inv.getArgument(0));
+        Path xlsx = writeDocs(tempDir, docRow("W-0101", "", "", "", "", "",
+                "1943-12-24", "24.12.1943", "DAY", ""));
+
+        importer.load(xlsx.toFile());
+
+        verify(documentService).save(org.mockito.ArgumentMatchers.argThat(d ->
+                d.getTitle().contains("24. Dezember 1943")));
+    }
+
+    @Test
+    void load_buildsTitleFromIndexOnly_whenDateUnknown(@TempDir Path tempDir) throws Exception {
+        ReflectionTestUtils.setField(importer, "importDir", tempDir.toString());
+        when(documentService.findByOriginalFilename("W-0102")).thenReturn(Optional.empty());
+        when(documentService.save(any())).thenAnswer(inv -> inv.getArgument(0));
+        Path xlsx = writeDocs(tempDir, docRow("W-0102", "", "", "", "", "",
+                "", "?", "UNKNOWN", ""));
+
+        importer.load(xlsx.toFile());
+
+        verify(documentService).save(org.mockito.ArgumentMatchers.argThat(d ->
+                d.getTitle().equals("W-0102")));
+    }
+
     // ─── helpers ─────────────────────────────────────────────────────────────────────
 
     private Map<String, String> docRow(String index, String file, String senderId, String senderName,