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>

app/api/admin/access-link/route.ts

@@ -0,0 +1,9 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { verifyAdminToken, getAdminToken } from '@/lib/auth/tokens';
+
+export async function GET(request: NextRequest) {
+  if (!verifyAdminToken(request)) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+  }
+  return NextResponse.json({ token: getAdminToken() });
+}