fix(fc3c): origin='downloaded' (existing enum value), not invented 'imported_download'

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

backend/app/services/importer.py

@@ -518,7 +518,7 @@ class Importer:
             mime=_mime_for(path),
             width=width,
             height=height,
-            origin="imported_download",
+            origin="downloaded",
             integrity_status="unknown",
         )
         if artist is not None:

tests/test_importer_attach_in_place.py

@@ -53,7 +53,7 @@ def test_attach_in_place_imports_happy(importer, db_sync):
         .where(ImageRecord.id == result.image_id)
     ).one()
     assert rec_path.path == str(target)
-    assert rec_path.origin == "imported_download"
+    assert rec_path.origin == "downloaded"
     assert rec_path.artist_id == artist.id