feat: grid layout, global claim/qty toggles, admin access link, swaddle image

- Public wishlist now renders as responsive 3-col grid instead of list
- Subtitle supports line breaks (whitespace-pre-line)
- claimingEnabled and showQuantity moved to global site settings (not per-item); toggled in admin Configurações panel; claim API enforces server-side
- Admin dashboard shows admin access link with copy button
- Settings API exposes and persists the two new boolean settings

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/api.ts

@@ -354,6 +354,8 @@ export const scrapingApi = {
 export interface Settings {
   siteTitle: string;
   homepageSubtext: string;
+  claimingEnabled: boolean;
+  showQuantity: boolean;
 }
 
 export const settingsApi = {