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/admin/src/api/upload.ts

@@ -0,0 +1,14 @@
+import request from './request'
+
+export interface UploadResult {
+  url: string
+  filename: string
+}
+
+export const uploadApi = {
+  uploadImage: (file: File) => {
+    const formData = new FormData()
+    formData.append('file', file)
+    return request.post<any, UploadResult>('/upload/image', formData)
+  },
+}