fix(review): adopt latest server_rev on PUT; retry once on 409

Review was POSTing price/sku to /review before each save; that endpoint
persists those overrides and bumps server_rev, so the following PUT sent
a stale client_rev and hit 409 — Continue to Publish stayed disabled.
Stop sending price/sku on review probes (PUT already persists them) and
have updateSlab refetch + retry once on revision_conflict.

frontend/src/api/slabs.ts

@@ -45,6 +45,9 @@ export interface Slab {
   inference_status: string | null;
   calibration_photo_id: string | null;
   woo_product_id: number | null;
+  /** Create-time optimistic token; updates compare against server_rev, not this. */
+  client_rev: number;
+  /** Optimistic concurrency token; send as client_rev on PUT. */
   server_rev: number;
   created_at: string;
   updated_at: string;
@@ -135,7 +138,7 @@ export function getSlab(id: string): Promise<Slab> {
   return fetch(`/api/v1/slabs/${encodeURIComponent(id)}`).then((r) => parse<Slab>(r));
 }
 
-export function updateSlab(id: string, patch: SlabInput & { client_rev: number }): Promise<Slab> {
+function putSlab(id: string, patch: SlabInput & { client_rev: number }): Promise<Slab> {
   return fetch(`/api/v1/slabs/${encodeURIComponent(id)}`, {
     method: 'PUT',
     headers: { 'Content-Type': 'application/json' },
@@ -143,6 +146,37 @@ export function updateSlab(id: string, patch: SlabInput & { client_rev: number }
   }).then((r) => parse<Slab>(r));
 }
 
+/**
+ * PUT a slab patch. `client_rev` must equal the slab's current `server_rev`.
+ * On 409 revision_conflict (stale rev — e.g. review POST bumped server_rev, or
+ * a concurrent save), refetch once, adopt the latest server_rev, and retry.
+ * A second 409 surfaces a clear reload message.
+ */
+export async function updateSlab(
+  id: string,
+  patch: SlabInput & { client_rev: number },
+): Promise<Slab> {
+  try {
+    return await putSlab(id, patch);
+  } catch (e) {
+    if (!(e instanceof ApiError) || e.status !== 409) throw e;
+    const latest = await getSlab(id);
+    try {
+      return await putSlab(id, { ...patch, client_rev: latest.server_rev });
+    } catch (e2) {
+      if (e2 instanceof ApiError && e2.status === 409) {
+        throw new ApiError(
+          409,
+          e2.code ?? 'revision_conflict',
+          'This slab changed elsewhere. Reload the page and try again.',
+          e2.detail,
+        );
+      }
+      throw e2;
+    }
+  }
+}
+
 export function deleteSlab(id: string): Promise<void> {
   return fetch(`/api/v1/slabs/${encodeURIComponent(id)}`, { method: 'DELETE' }).then((r) =>
     parse<void>(r),