feat(admin): remove or restore every background on an item (#293)

Two routes on the item, and a small admin config route so the inventory screen can know whether to offer them.

Both answer 200 once the id is valid, even when the sidecar fails, and that is a deliberate departure from the per-photo endpoints in #281. Those act on one image, so the request either worked or it did not and 502 says which. These act on several, so "did it work" has no single answer — two of four is the normal shape of a bad day here, not an exception — and a 502 would throw away the count that is the only thing making the outcome actionable. Non-200 is reserved for not being able to try at all, which here means an unreadable or absent id.

No status check on either. A sold item's photos are still the shop's photos and improving them changes nothing about the sale; the guards on unpublish protect a checkout in progress and a completed sale, neither of which is at stake in a photograph's background.

The config route follows adminVersion's precedent rather than extending the public /api/config: admin-only, one purpose, and the reason written down. The inventory screen had no other way to learn the feature exists, because GET /api/admin/items answers a bare array with several consumers and reshaping it for one boolean is the worse trade.

Also extends the admin item select to carry original_image_path on each image, behind a new ADMIN_IMAGES_SUBQUERY kept separate from the shared IMAGES_SUBQUERY the public select uses. Task 3 needs to derive its restore-button label from that field, and the server never sent it for items before this — only the drafts endpoint carried it, added by #281 for the review queue. It stays admin-only for the same reason itemSelect.ts already names PUBLIC_ITEM_SELECT's columns explicitly: an internal original filename is nobody's business on the storefront, and sharing one subquery would put it in every public item response.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

backend/src/itemSelect.ts

@@ -30,6 +30,26 @@ const IMAGES_SUBQUERY = `
     WHERE img.item_id = i.id
   ), '[]') AS images`;
 
+/**
+ * Admin-only images, carrying `original_image_path` alongside the public
+ * fields — the field the inventory screen needs to know whether a photo has a
+ * cut-out to restore (#293).
+ *
+ * A separate subquery rather than adding the column to `IMAGES_SUBQUERY`
+ * itself, for the same reason `PUBLIC_ITEM_SELECT` names its columns instead
+ * of using `i.*`: an original filename is internal — nobody's business on the
+ * storefront — and folding it into the one subquery both selects share would
+ * put it in every public item response too.
+ */
+const ADMIN_IMAGES_SUBQUERY = `
+  COALESCE((
+    SELECT json_agg(json_build_object('id', img.id, 'image_path', img.image_path, 'sort_order', img.sort_order,
+                                       'original_image_path', img.original_image_path)
+                    ORDER BY img.sort_order)
+    FROM item_images img
+    WHERE img.item_id = i.id
+  ), '[]') AS images`;
+
 const TAGS_SUBQUERY = `
   COALESCE((
     SELECT json_agg(json_build_object('id', t.id, 'name', t.name, 'color', t.color) ORDER BY t.name)
@@ -54,7 +74,7 @@ export const PUBLIC_ITEM_SELECT = `
 export const ADMIN_ITEM_SELECT = `
   SELECT i.*,
     c.name AS category_name,
-    ${IMAGES_SUBQUERY},
+    ${ADMIN_IMAGES_SUBQUERY},
     ${TAGS_SUBQUERY}
   ${FROM_CLAUSE}`;
 
@@ -89,16 +109,28 @@ interface ItemRowBase {
 /** What PUBLIC_ITEM_SELECT returns. Deliberately no payment or reservation columns. */
 export type PublicItemRow = ItemRowBase;
 
+/**
+ * An admin item's image: everything `ItemImage` has, plus where the
+ * background-removed photo's original went. `null` for a photo that was never
+ * cut out.
+ */
+export interface AdminItemImage extends ItemImage {
+  original_image_path: string | null;
+}
+
 /**
  * What ADMIN_ITEM_SELECT returns: `i.*`, so every column on the table.
  *
  * The extra fields are the ones the storefront is not allowed to see, which is
- * the whole reason the two selects differ.
+ * the whole reason the two selects differ. `images` is narrowed rather than
+ * inherited as-is, to match `ADMIN_IMAGES_SUBQUERY` carrying
+ * `original_image_path` where the public select's images do not.
  */
 export interface AdminItemRow extends ItemRowBase {
   reserved_until: Date | null;
   sold_at: Date | null;
   paypal_order_id: string | null;
+  images: AdminItemImage[];
 }
 
 /**