feat: allow retrieve API store method to use cached results

The cached result is usually sufficient and we don’t necessarily need
fresh data from the API.

src/api.ts

@@ -132,7 +132,15 @@ export function APIListUnpaginated<T extends APIObject>(api: ExtendableAPI<T>) {
   return { list }
 }
 export function APIRetrieve<T extends APIObject>(api: ExtendableAPI<T>) {
-  async function retrieve(id: ID, requestInit?: RequestInit): Promise<T | null> {
+  async function retrieve(
+    id: ID,
+    requestInit?: RequestInit,
+    options?: { useCached?: boolean },
+  ): Promise<T | null> {
+    if (options?.useCached && api.itemMap.value.has(id)) {
+      return api.itemMap.value.get(id) as T
+    }
+
     const res = await fetch(api.createRequest(api.endpoint(id.toString()), requestInit))
     if (res.status === 404) {
       api.itemMap.value.delete(id)