Update seller store experience

packages/database/migrations/015_collection_asset_pending_selection.sql

@@ -0,0 +1,5 @@
+SET search_path TO atlas, public;
+
+-- Source-image candidates are recorded during collection but are not fetched
+-- until the user actually selects one for editing, processing or publishing.
+ALTER TYPE processing_status ADD VALUE IF NOT EXISTS 'pending_selection';