feat: member portal Sprint 11 — Memories / Gallery

- GalleryAlbum + GalleryItem models + migration (publish gate, cover image, ordered items)
- GalleryModule: admin CRUD for albums + items
- Member endpoints: GET /my/memories (published albums w/ cover + count), GET /my/memories/:id (album + photos)
- /my/memories page: album grid with cover thumbnails
- /my/memories/[id] page: photo grid with captions
- Memories nav item; register GalleryModule

Completes Phase 2 (Intelligence) of the member portal — Sprints 9-11.

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

apps/web/app/my/layout.tsx

@@ -11,6 +11,7 @@ const NAV = [
   { href: '/my/seva', label: 'Seva & Points' },
   { href: '/my/circles', label: 'Circles' },
   { href: '/my/directory', label: 'Directory' },
+  { href: '/my/memories', label: 'Memories' },
   { href: '/my/groups', label: 'My Groups' },
   { href: '/my/settings', label: 'Settings' },
 ];