Remove unneeded function

lib/core/services/storage_service.dart

@@ -211,50 +211,6 @@ class StorageService {
     return null;
   }
 
-  /// Reads annotations with metadata for a specific sheet page.
-  ///
-  /// Returns [StoredAnnotation] with annotations and lastModified, or null if none exist.
-  Future<StoredAnnotation?> readAnnotationsWithMetadata(
-    String sheetUuid,
-    int pageNumber,
-  ) async {
-    final box = await Hive.openBox(_annotationsBox);
-    final value = box.get(_annotationKey(sheetUuid, pageNumber));
-
-    if (value == null) return null;
-
-    // Handle legacy format (plain string) - treat as very old
-    if (value is String) {
-      return StoredAnnotation(
-        annotationsJson: value,
-        lastModified: DateTime.fromMillisecondsSinceEpoch(0),
-      );
-    }
-
-    if (value is Map) {
-      return StoredAnnotation.fromMap(value);
-    }
-
-    return null;
-  }
-
-  /// Writes annotations for a specific sheet page.
-  ///
-  /// Pass null or empty string to delete annotations for that page.
-  /// Automatically sets lastModified to current time.
-  Future<void> writeAnnotations(
-    String sheetUuid,
-    int pageNumber,
-    String? annotationsJson,
-  ) async {
-    await writeAnnotationsWithMetadata(
-      sheetUuid,
-      pageNumber,
-      annotationsJson,
-      DateTime.now(),
-    );
-  }
-
   /// Writes annotations with a specific lastModified timestamp.
   ///
   /// Used when syncing from server to preserve server's timestamp.