feat(frontend): a finished action answers on the button that was pressed instead of a toast

frontend/src/lib/components/stories/AllStoriesArchive.svelte

@@ -18,6 +18,7 @@
   import { peerName } from "#lib/format/peer.js";
   import { t } from "#lib/i18n/locale.svelte.js";
   import { accounts } from "#lib/stores/accounts.svelte.js";
+  import { createFlash } from "#lib/stores/flash.svelte.js";
   import { toasts } from "#lib/stores/toasts.svelte.js";
 
   interface Group {
@@ -45,6 +46,7 @@
   let viewerItems = $state<StoryView[]>([]);
   let viewerPeerId = $state(0);
   let backfilling = $state<number | null>(null);
+  const started = createFlash<number>();
 
   async function load() {
     const current = token;
@@ -150,7 +152,7 @@
     backfilling = peerId;
     try {
       await enqueueStoriesBackfill(peerId);
-      toasts.success(t("stories.backfillStarted"));
+      started.show(peerId);
     } catch {
       toasts.error(t("stories.backfillFailed"));
     } finally {
@@ -178,6 +180,10 @@
   {/if}
 {:else}
   {#each groups as group (group.peerId)}
+    {@const fresh = started.current === group.peerId}
+    {@const backfillLabel = fresh
+      ? t("stories.backfillStarted")
+      : t("stories.loadOlderStories")}
     <section class="group">
       <header class="group-head">
         <button
@@ -200,14 +206,15 @@
           </span>
         </button>
         <Button
-          aria-label={t("stories.loadOlderStories")}
+          aria-label={backfillLabel}
           loading={backfilling === group.peerId}
           onclick={() => backfill(group.peerId)}
           round
           smaller
+          title={backfillLabel}
           variant="translucent"
         >
-          <Icon name="cloud-download" />
+          <Icon name={fresh ? "check" : "cloud-download"} />
         </Button>
       </header>
       {#if expanded[group.peerId]}