Items in the Square "Build" category don't need the "Online" category
to appear in the bouquet builder. A new /api/bouquet-items endpoint
calls getSquareCatalog({ filterCategory: 'build' }) which skips the
Online filter and returns only Build-category items directly from Square.
BouquetPicker now fetches from /api/bouquet-items instead of /api/catalog.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>