feat(attachments): scan enumerates all; import_file maps 'attached' + member ML

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/app/tasks/import_file.py

@@ -26,11 +26,12 @@ IMAGES_ROOT = Path("/images")
 
 def _map_result_to_status(result):
     """(ImportTask.status, should_requeue_ml_and_thumb) for an ImportResult.
-    'superseded' = the kept row's file/ML changed → complete + re-derive."""
-    if result.status == "imported":
-        return ("complete", True)
-    if result.status == "superseded":
+    'superseded' = the kept row's file/ML changed → complete + re-derive.
+    'attached' = a non-art file preserved → complete, no ML/thumb."""
+    if result.status in ("imported", "superseded"):
         return ("complete", True)
+    if result.status == "attached":
+        return ("complete", False)
     if result.status == "skipped":
         return ("skipped", False)
     return ("failed", False)
@@ -82,6 +83,10 @@ def import_media_file(self, import_task_id: int) -> dict:
             task.result_image_id = result.image_id
             counter_col_name = "imported"
             counter_col = ImportBatch.imported
+        elif result.status == "attached":
+            task.status = "complete"
+            counter_col_name = "attachments"
+            counter_col = ImportBatch.attachments
         elif result.status == "skipped":
             task.status = "skipped"
             task.error = (
@@ -109,15 +114,16 @@ def import_media_file(self, import_task_id: int) -> dict:
 
         # Enqueue thumbnail + ML for newly imported AND superseded images
         # (a superseded row has cleared ML + no thumbnail).
-        if (
-            result.status in ("imported", "superseded")
-            and result.image_id is not None
-        ):
+        if result.status in ("imported", "superseded"):
             from .ml import tag_and_embed
             from .thumbnail import generate_thumbnail
 
-            generate_thumbnail.delay(result.image_id)
-            tag_and_embed.delay(result.image_id)
+            ids = list(result.member_image_ids)
+            if result.image_id is not None and result.image_id not in ids:
+                ids.append(result.image_id)
+            for img_id in ids:
+                generate_thumbnail.delay(img_id)
+                tag_and_embed.delay(img_id)
 
         # If this was the last task in the batch, mark the batch complete.
         remaining = session.execute(