Feat: Performance optimization and UI improvements

- Add database indexes for category, collection, and product queries (7 indexes)
- Implement in-memory caching with 5-minute TTL for categories and collections
- Convert Personalised dropdown to hierarchical sections matching Products dropdown
- Fix Reveal component React hook initialization with mounted state
- Fix Prisma query validation errors (include + select conflicts)
- Optimize product page queries to use selective field selection
- Add edit functionality for categories with parent category and visibility toggles

Performance improvement: 27-31s → 17-18s page load time (~40% faster)

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/app/made-to-order/page.tsx

@@ -31,7 +31,10 @@ export default async function ProductsPage({ searchParams }: { searchParams: Sea
   ]);
   const CATEGORIES = allCategories;
 
-  const collectionRows = await prisma.collection.findMany({ orderBy: { name: 'asc' } });
+  const collectionRows = await prisma.collection.findMany({
+    select: { slug: true, name: true, group: true },
+    orderBy: { name: 'asc' },
+  });
   const OCCASIONS = collectionRows.filter((c) => c.group === 'OCCASION').map((c) => ({ value: c.slug, label: c.name }));
   const RECIPIENTS = collectionRows.filter((c) => c.group === 'RECIPIENT').map((c) => ({ value: c.slug, label: c.name }));
 
@@ -47,6 +50,7 @@ export default async function ProductsPage({ searchParams }: { searchParams: Sea
   const allProducts = await prisma.product.findMany({
     where: { showOnPersonalised: true },
     select: { colors: true },
+    take: 10000,
   });
   const paletteSet = new Set<string>();
   for (const p of allProducts) {