feat(product-center): implement Figma-designed UI, upload module, and website tests

- Redesign website homepage & product-center per Figma (fonts, logos, hero/footer/customer cases)
- Add API upload module (multer) with static serving for uploads/public assets
- Add OriginGood.delisted flag and SDS request retry logic
- Add admin ImageUpload component and goods import/upload flows
- Add vitest suite for website components and composables (32 tests)
- Add skills, docs, plans and PRODUCT.md

apps/website/test/ProductSidebar.test.ts

@@ -0,0 +1,25 @@
+import { mount } from '@vue/test-utils';
+import { describe, expect, it } from 'vitest';
+import ProductSidebar from '../app/components/product/ProductSidebar.vue';
+import type { Category } from '../app/composables/useProductCenter';
+
+const categories: Category[] = [{
+  id: 'men',
+  name: '男士服装',
+  icon: null,
+  parentId: null,
+  children: [{ id: 'men-tee', name: 'T恤', icon: null, parentId: 'men', children: [] }],
+}];
+
+describe('ProductSidebar', () => {
+  it('selects and expands a parent category when it is clicked', async () => {
+    const wrapper = mount(ProductSidebar, {
+      props: { categories, activeCategoryId: null },
+    });
+
+    await wrapper.findAll('.root-row')[1]?.trigger('click');
+
+    expect(wrapper.emitted('update:activeCategoryId')).toEqual([['men']]);
+    expect(wrapper.text()).toContain('T恤');
+  });
+});