feat(handleTitleStatusChanged): create reusable handler for sections title status management

src/entities/Breadcrumb/model/services/handleTitleStatusChanged/handleTitleStatusChanged.ts

@@ -0,0 +1,29 @@
+import type { TitleStatusChangeHandler } from '$shared/ui';
+import type { Snippet } from 'svelte';
+import { scrollBreadcrumbsStore } from '../../store/scrollBreadcrumbsStore.svelte';
+
+/**
+ * Updates the breadcrumb store when the title visibility status changes.
+ *
+ * @param index - Index of the section
+ * @param isPast - Whether the section is past the current scroll position
+ * @param title - Snippet for a title itself
+ * @param id - ID of the section
+ * @returns Cleanup callback
+ */
+export const handleTitleStatusChanged: TitleStatusChangeHandler = (
+    index: number,
+    isPast: boolean,
+    title?: Snippet<[{ className?: string }]>,
+    id?: string,
+) => {
+    if (isPast && title) {
+        scrollBreadcrumbsStore.add({ index, title, id });
+    } else {
+        scrollBreadcrumbsStore.remove(index);
+    }
+
+    return () => {
+        scrollBreadcrumbsStore.remove(index);
+    };
+};