Add media gallery with album organization and Puck integration

Backend:
- Add Album and MediaFile models for tenant-scoped media storage
- Add TenantStorageUsage model for per-tenant storage quota tracking
- Create StorageQuotaService with EntitlementService integration
- Add AlbumViewSet, MediaFileViewSet with bulk operations
- Add StorageUsageView for quota monitoring

Frontend:
- Create MediaGalleryPage with album management and file upload
- Add drag-and-drop upload with storage quota validation
- Create ImagePickerField custom Puck field for gallery integration
- Update Image, Testimonial components to use ImagePicker
- Add background image picker to Puck design controls
- Add gallery to sidebar navigation

Also includes:
- Puck marketing components (Hero, SplitContent, etc.)
- Enhanced ContactForm and BusinessHours components
- Platform login page improvements
- Site builder draft/preview enhancements

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/src/components/Sidebar.tsx

@@ -19,6 +19,7 @@ import {
   CalendarOff,
   LayoutTemplate,
   MapPin,
+  Image,
 } from 'lucide-react';
 import { Business, User } from '../types';
 import { useLogout } from '../hooks/useAuth';
@@ -161,6 +162,12 @@ const Sidebar: React.FC<SidebarProps> = ({ business, user, isCollapsed, toggleCo
               isCollapsed={isCollapsed}
               badgeElement={<UnfinishedBadge />}
             />
+            <SidebarItem
+              to="/dashboard/gallery"
+              icon={Image}
+              label={t('nav.gallery', 'Media Gallery')}
+              isCollapsed={isCollapsed}
+            />
             <SidebarItem
               to="/dashboard/customers"
               icon={Users}