feat(product): 实现产品需求管理模块（后端 + 前端）

后端：Product Module（CRUD）、Requirement Module（CRUD + 状态机流转）、PrismaService
前端：产品列表页、产品详情页（含需求池 Tab）、Zustand Store、API 封装

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/components/product/ProductCard.tsx

@@ -0,0 +1,30 @@
+'use client';
+
+import { Product } from '@ftb/shared';
+
+interface ProductWithCount extends Product {
+  _count?: { requirements: number; projects: number };
+}
+
+interface Props {
+  product: ProductWithCount;
+  onClick: (id: string) => void;
+}
+
+export function ProductCard({ product, onClick }: Props) {
+  return (
+    <div
+      className="cursor-pointer rounded-lg border border-gray-200 p-5 transition-shadow hover:shadow-md"
+      onClick={() => onClick(product.id)}
+    >
+      <h3 className="text-lg font-semibold text-gray-900">{product.name}</h3>
+      {product.description && (
+        <p className="mt-1 text-sm text-gray-500 line-clamp-2">{product.description}</p>
+      )}
+      <div className="mt-4 flex gap-4 text-xs text-gray-400">
+        <span>{product._count?.requirements ?? 0} 需求</span>
+        <span>{product._count?.projects ?? 0} 项目</span>
+      </div>
+    </div>
+  );
+}