chore(CheckboxFilter): add stories for CheckboxFilter

src/shared/ui/CheckboxFilter/CheckboxFilter.stories.svelte

@@ -0,0 +1,37 @@
+<script module>
+import { createFilter } from '$shared/lib';
+import { defineMeta } from '@storybook/addon-svelte-csf';
+import CheckboxFilter from './CheckboxFilter.svelte';
+
+const { Story } = defineMeta({
+    title: 'Shared/CheckboxFilter',
+    tags: ['autodocs'],
+    parameters: {
+        docs: {
+            story: { inline: false }, // Render stories in iframe for state isolation
+        },
+    },
+});
+</script>
+
+<script lang="ts">
+const filter = createFilter({
+    properties: [{
+        id: 'cats',
+        name: 'Cats',
+        value: 'cats',
+    }, {
+        id: 'dogs',
+        name: 'Dogs',
+        value: 'dogs',
+    }, {
+        id: 'birds',
+        name: 'Birds',
+        value: 'birds',
+    }],
+});
+</script>
+
+<Story name="Default">
+    <CheckboxFilter {filter} displayedLabel="Zoo" />
+</Story>