Add product search with autocomplete, filters, and sort

- Header: search button opening a command-palette dialog with debounced
  product suggestions, a term chip, and View All
- Command: shadcn-shaped primitives built on the project's own Dialog so
  no cmdk/radix dependency is introduced
- /search: results grid with item count, sort (relevance, price asc/desc),
  and cursor-based load more
- Filters: driven by the API's productFilters facets — colour swatches,
  labelled lists with counts, and a price range — round-tripped through
  each facet's raw input string so no filter shape is hardcoded

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

app/search/page.tsx

@@ -0,0 +1,33 @@
+import { Suspense } from 'react';
+import Header from '@/components/shopify/header';
+import Footer from '@/components/shopify/footer';
+import SearchResults from '@/components/shopify/search-results';
+
+export const metadata = {
+  title: 'Search — Shop',
+};
+
+export default function Page() {
+  return (
+    <>
+      <Header
+        storeName="Shop"
+        logoUrl=""
+        links={[
+          { label: 'Products', url: '/' },
+          { label: 'Collections', url: '/collections' },
+        ]}
+      />
+
+      {/* useSearchParams needs a Suspense boundary to prerender this route. */}
+      <Suspense fallback={<div className="py-10" />}>
+        <SearchResults />
+      </Suspense>
+
+      <Footer
+        storeName="Shop"
+        copyright="© 2026 Shop. All rights reserved."
+      />
+    </>
+  );
+}