feat(SampleList): remove text loader and add a prop isLoading

src/widgets/SampleList/ui/SampleList/SampleList.svelte

@@ -50,11 +50,9 @@ const displayRange = $derived.by(() => {
     const loadedCount = Math.min(offset + limit, total);
     return `Showing ${loadedCount} of ${total} fonts`;
 });
-</script>
 
-{#if unifiedFontStore.isFetching || unifiedFontStore.isLoading}
-    <span class="ml-2 text-xs text-muted-foreground/70">(Loading...)</span>
-{/if}
+const isLoading = $derived(unifiedFontStore.isFetching || unifiedFontStore.isLoading);
+</script>
 
 <FontVirtualList
     items={unifiedFontStore.fonts}
@@ -63,8 +61,15 @@ const displayRange = $derived.by(() => {
     itemHeight={280}
     useWindowScroll={true}
     weight={controlManager.weight}
+    {isLoading}
 >
-    {#snippet children({ item: font, isFullyVisible, isPartiallyVisible, proximity, index })}
+    {#snippet children({
+    item: font,
+    isFullyVisible,
+    isPartiallyVisible,
+    proximity,
+    index,
+})}
         <FontListItem {font} {isFullyVisible} {isPartiallyVisible} {proximity}>
             <FontSampler {font} bind:text {index} />
         </FontListItem>