feat(Skeleton): create skeleton component and integrate it into FontVirtualList

src/entities/Font/ui/FontVirtualList/FontVirtualList.svelte

@@ -4,8 +4,12 @@
     - Handles font registration with the manager
 -->
 <script lang="ts" generics="T extends UnifiedFont">
-import { VirtualList } from '$shared/ui';
+import {
+    Skeleton,
+    VirtualList,
+} from '$shared/ui';
 import type { ComponentProps } from 'svelte';
+import { fade } from 'svelte/transition';
 import { getFontUrl } from '../../lib';
 import type { FontConfigRequest } from '../../model';
 import {
@@ -13,13 +17,42 @@ import {
     appliedFontsManager,
 } from '../../model';
 
-interface Props extends Omit<ComponentProps<typeof VirtualList<T>>, 'onVisibleItemsChange'> {
+interface Props extends
+    Omit<
+        ComponentProps<typeof VirtualList<T>>,
+        'onVisibleItemsChange'
+    >
+{
+    /**
+     * Callback for when visible items change
+     */
     onVisibleItemsChange?: (items: T[]) => void;
+    /**
+     * Callback for when near bottom is reached
+     */
     onNearBottom?: (lastVisibleIndex: number) => void;
+    /**
+     * Weight of the font
+     */
+    /**
+     * Weight of the font
+     */
     weight: number;
+    /**
+     * Whether the list is in a loading state
+     */
+    isLoading?: boolean;
 }
 
-let { items, children, onVisibleItemsChange, onNearBottom, weight, ...rest }: Props = $props();
+let {
+    items,
+    children,
+    onVisibleItemsChange,
+    onNearBottom,
+    weight,
+    isLoading = false,
+    ...rest
+}: Props = $props();
 
 function handleInternalVisibleChange(visibleItems: T[]) {
     const configs: FontConfigRequest[] = [];
@@ -50,13 +83,31 @@ function handleNearBottom(lastVisibleIndex: number) {
 }
 </script>
 
-<VirtualList
-    {items}
-    {...rest}
-    onVisibleItemsChange={handleInternalVisibleChange}
-    onNearBottom={handleNearBottom}
->
-    {#snippet children(scope)}
-        {@render children(scope)}
-    {/snippet}
-</VirtualList>
+{#key isLoading}
+    <div class="relative w-full h-full" transition:fade={{ duration: 300 }}>
+        {#if isLoading}
+            <div class="flex flex-col gap-4 p-4">
+                {#each Array(5) as _, i}
+                    <div class="flex flex-col gap-2 p-4 border rounded-xl border-gray-200/50 bg-white/40">
+                        <div class="flex items-center justify-between mb-4">
+                            <Skeleton class="h-8 w-1/3" />
+                            <Skeleton class="h-8 w-8 rounded-full" />
+                        </div>
+                        <Skeleton class="h-32 w-full" />
+                    </div>
+                {/each}
+            </div>
+        {:else}
+            <VirtualList
+                {items}
+                {...rest}
+                onVisibleItemsChange={handleInternalVisibleChange}
+                onNearBottom={handleNearBottom}
+            >
+                {#snippet children(scope)}
+                    {@render children(scope)}
+                {/snippet}
+            </VirtualList>
+        {/if}
+    </div>
+{/key}