feat(434): facet-value typeahead combobox for text fields

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/api/search.ts

@@ -15,6 +15,21 @@ export function getSearchFields(): Promise<SearchField[]> {
   return request<SearchField[]>('/api/v1/search/fields');
 }
 
+export type SearchFieldValues = components['schemas']['SearchFieldValuesResponseModel'];
+
+// Backs the rule builder's facet-value typeahead (#434): distinct values a text field already holds
+// in the library, matching the in-progress query prefix. `.values` is non-nullable on the DTO, but we
+// still coerce defensively at the boundary (Core-DTO-nullable convention) in case a future model
+// change reintroduces nullability.
+export function getSearchFieldValues(name: string, q: string, limit = 50): Promise<string[]> {
+  const searchParams = new URLSearchParams();
+  searchParams.set('q', q);
+  searchParams.set('limit', String(limit));
+  return request<SearchFieldValues>(`/api/v1/search/fields/${encodeURIComponent(name)}/values?${searchParams.toString()}`).then(
+    (result) => result.values ?? []
+  );
+}
+
 // The ten media-item id arrays a search query resolves to, one bucket per addable kind. Wire keys
 // match AddItemsToCollectionRequest exactly, so a result pipes straight into addItemsToCollection /
 // addItemsToPlaylist via toAddItemsRequestFromSearch below.