Add AI store assistant with catalogue tool calls

- /api/chat streams via AI SDK v7 through OpenRouter (OPENROUTER_API_KEY),
  with a store-specific system prompt and five read-only tools:
  searchCatalogue, getProductDetails, listCollections,
  getCollectionProducts, browseProducts
- Sidebar assistant on the right that opens from a launcher and expands,
  built on ai-elements (conversation, message, prompt-input, tool) with
  shimmer on in-flight tool calls
- Extract services/shopify/catalog.ts so the Storefront fetchers have no
  React imports and can run in a Route Handler; the client hooks now
  re-export from it
- ai-elements pulled in the canonical shadcn primitives, replacing the
  hand-rolled command/dialog/button variants; search dialog moved to the
  cmdk-based Command and CommandDialog forwards shouldFilter
- Pin shiki to ^3.19.0 to match streamdown and drop the duplicate copy
- Add .env.example documenting the required env vars

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016jWbNNJLksC1QG8z8845FX

hooks/use-shopify-products.ts

@@ -1,99 +1,37 @@
 'use client';
 
 import { useState, useEffect, useCallback } from 'react';
-import { shopifyFetch } from '@/services/shopify/client';
 import {
-  GET_PRODUCTS_QUERY,
-  GET_PRODUCT_QUERY,
-  QUERY_PRODUCT_RECOMMENDATIONS,
-} from '@/graphql/products';
+  getProducts,
+  getProduct,
+  getProductRecommendations,
+} from '@/services/shopify/catalog';
 
-interface ProductImage {
-  url: string;
-  altText?: string;
-}
+// Pure fetchers live in services/shopify/catalog so server code can use them
+// too; re-exported here so existing imports keep working.
+export {
+  getProducts,
+  getProductsPage,
+  getProduct,
+  getProductRecommendations,
+} from '@/services/shopify/catalog';
+export type {
+  Product,
+  ProductOption,
+  ProductOptionValue,
+  ProductsPage,
+} from '@/services/shopify/catalog';
 
-interface ProductPrice {
-  amount: string;
-  currencyCode: string;
-}
-
-interface ProductVariant {
-  id: string;
-  title: string;
-  price: ProductPrice;
-  availableForSale: boolean;
-  selectedOptions: Array<{
-    name: string;
-    value: string;
-  }>;
-  image?: ProductImage;
-}
-
-export interface ProductOptionValue {
-  id: string;
-  name: string;
-  swatch?: {
-    color?: string | null;
-    image?: {
-      previewImage?: {
-        url: string;
-      } | null;
-    } | null;
-  } | null;
-  firstSelectableVariant?: {
-    id: string;
-    image?: ProductImage | null;
-  } | null;
-}
-
-export interface ProductOption {
-  id: string;
-  name: string;
-  values: string[];
-  optionValues?: ProductOptionValue[];
-}
-
-export interface Product {
-  id: string;
-  title: string;
-  description?: string;
-  descriptionHtml?: string;
-  handle: string;
-  images: {
-    edges: Array<{
-      node: ProductImage;
-    }>;
-  };
-  priceRange: {
-    minVariantPrice: ProductPrice;
-  };
-  compareAtPriceRange?: {
-    minVariantPrice: ProductPrice;
-  };
-  variants: {
-    edges: Array<{
-      node: ProductVariant;
-    }>;
-  };
-  options: ProductOption[];
-}
+import type { Product } from '@/services/shopify/catalog';
 
 interface UseProductsOptions {
   first?: number;
-  /** Cursor from a previous page's `endCursor`; omit for the first page. */
   after?: string | null;
   query?: string;
   sortKey?: 'BEST_SELLING' | 'CREATED_AT' | 'PRICE' | 'TITLE';
   reverse?: boolean;
 }
 
-export interface ProductsPage {
-  products: Product[];
-  hasNextPage: boolean;
-  endCursor: string | null;
-}
-
 interface UseProductsReturn {
   products: Product[];
   loading: boolean;
@@ -101,56 +39,6 @@ interface UseProductsReturn {
   refetch: () => Promise<void>;
 }
 
-// Fetch multiple products
-export async function getProducts(
-  options: UseProductsOptions = {}
-): Promise<Product[]> {
-  const { products } = await getProductsPage(options);
-  return products;
-}
-
-// Same fetch, but keeps the cursor so callers can page through the catalogue.
-export async function getProductsPage({
-  first = 20,
-  after = null,
-  query = '',
-  sortKey = 'BEST_SELLING',
-  reverse = false,
-}: UseProductsOptions = {}): Promise<ProductsPage> {
-  const response = await shopifyFetch({
-    query: GET_PRODUCTS_QUERY,
-    variables: { first, after, query, sortKey, reverse },
-  });
-
-  const { edges, pageInfo } = response.data.products;
-
-  return {
-    products: edges.map((edge: { node: Product }) => edge.node),
-    hasNextPage: Boolean(pageInfo?.hasNextPage),
-    endCursor: pageInfo?.endCursor ?? null,
-  };
-}
-
-// Fetch a single product by handle
-export async function getProduct(handle: string): Promise<Product | null> {
-  const response = await shopifyFetch({
-    query: GET_PRODUCT_QUERY,
-    variables: { handle },
-  });
-
-  return response.data.product;
-}
-
-// Fetch product recommendations
-export async function getProductRecommendations(productId: string): Promise<Product[]> {
-  const response = await shopifyFetch({
-    query: QUERY_PRODUCT_RECOMMENDATIONS,
-    variables: { productId },
-  });
-
-  return response.data.productRecommendations || [];
-}
-
 // Hook for fetching multiple products
 export function useProducts(options: UseProductsOptions = {}): UseProductsReturn {
   const [products, setProducts] = useState<Product[]>([]);