feat(Breadcrumb): create new entity that contains logic related to breadcrumb-like navigation

src/entities/Breadcrumb/index.ts

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+export { scrollBreadcrumbsStore } from './model';
+export { BreadcrumbHeader } from './ui';

src/entities/Breadcrumb/model/index.ts

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+export * from './store/scrollBreadcrumbsStore.svelte';

src/entities/Breadcrumb/model/store/scrollBreadcrumbsStore.svelte.ts

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+import type { Snippet } from 'svelte';
+
+export interface BreadcrumbItem {
+    index: number;
+    title: Snippet<[{ className?: string }]>;
+}
+
+class ScrollBreadcrumbsStore {
+    #items = $state<BreadcrumbItem[]>([]);
+
+    get items() {
+        // Keep them sorted by index for Swiss orderliness
+        return this.#items.sort((a, b) => a.index - b.index);
+    }
+    add(item: BreadcrumbItem) {
+        if (!this.#items.find(i => i.index === item.index)) {
+            this.#items.push(item);
+        }
+    }
+    remove(index: number) {
+        this.#items = this.#items.filter(i => i.index !== index);
+    }
+}
+
+export function createScrollBreadcrumbsStore() {
+    return new ScrollBreadcrumbsStore();
+}
+
+export const scrollBreadcrumbsStore = createScrollBreadcrumbsStore();

src/entities/Breadcrumb/ui/BreadcrumbHeader/BreadcrumbHeader.svelte

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+<!--
+    Component: BreadcrumbHeader
+    Fixed header for breadcrumbs navigation for sections in the page
+-->
+<script lang="ts">
+import Icon from '@lucide/svelte/icons/align-vertical-justify-center';
+import { flip } from 'svelte/animate';
+import { slide } from 'svelte/transition';
+import { scrollBreadcrumbsStore } from '../../model';
+</script>
+
+{#if scrollBreadcrumbsStore.items.length > 0}
+    <div
+        transition:slide={{ duration: 200 }}
+        class="
+            fixed top-0 left-0 right-0 z-100
+            backdrop-blur-lg bg-white/20
+            border-b border-gray-300/50
+            shadow-[0_1px_3px_rgba(0,0,0,0.04)]
+            h-12
+        "
+    >
+        <div class="max-w-8xl mx-auto px-6 h-full flex items-center gap-4">
+            <div class="flex items-center gap-2.5 opacity-70">
+                <Icon class="size-4 stroke-gray-900 stroke-1" />
+                <div class="w-px h-2.5 bg-gray-400/50"></div>
+                <span class="font-mono text-[9px] uppercase tracking-[0.25em] text-gray-500 font-medium">
+                    nav_trace
+                </span>
+            </div>
+
+            <div class="h-4 w-px bg-gray-300/60"></div>
+
+            <nav class="flex items-center gap-3 overflow-x-auto scrollbar-hide flex-1">
+                {#each scrollBreadcrumbsStore.items as item, idx (item.index)}
+                    <div
+                        animate:flip={{ duration: 200 }}
+                        class="flex items-center gap-3 whitespace-nowrap shrink-0"
+                    >
+                        <span class="font-mono text-[9px] text-gray-400 tracking-wider">
+                            {String(item.index).padStart(2, '0')}
+                        </span>
+
+                        {@render item.title({
+    className: 'font-mono text-[10px] font-bold uppercase tracking-tight leading-[0.95] text-gray-900',
+})}
+
+                        {#if idx < scrollBreadcrumbsStore.items.length - 1}
+                            <div class="flex items-center gap-0.5 opacity-40">
+                                <div class="w-1 h-px bg-gray-400"></div>
+                                <div class="w-1 h-px bg-gray-400"></div>
+                                <div class="w-1 h-px bg-gray-400"></div>
+                            </div>
+                        {/if}
+                    </div>
+                {/each}
+            </nav>
+
+            <div class="flex items-center gap-2 opacity-50 ml-auto">
+                <div class="w-px h-2.5 bg-gray-300/60"></div>
+                <span class="font-mono text-[8px] text-gray-400 tracking-wider">
+                    [{scrollBreadcrumbsStore.items.length}]
+                </span>
+            </div>
+        </div>
+    </div>
+{/if}
+
+<style>
+/* Hide scrollbar but keep functionality */
+.scrollbar-hide {
+    -ms-overflow-style: none;
+    scrollbar-width: none;
+}
+.scrollbar-hide::-webkit-scrollbar {
+    display: none;
+}
+</style>

src/entities/Breadcrumb/ui/index.ts

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+import BreadcrumbHeader from './BreadcrumbHeader/BreadcrumbHeader.svelte';
+
+export { BreadcrumbHeader };