feat(ui): Components refactoring with Tailwind - UI kit, icons, lazy loading images

- Created reusable UI components (Card, Button, Badge, Form, Icon)
- Added PageIcon and NavIcon components with consistent styling
- Refactored all pages to use new UI components
- Added non-blocking image loading with skeleton for book covers
- Created LibraryActions dropdown for library settings
- Added emojis to buttons for better UX
- Fixed Client Component issues with getBookCoverUrl

apps/backoffice/app/globals.css

@@ -17,6 +17,9 @@
   --color-error-soft: hsl(2 72% 90%);
   
   --font-sans: "Avenir Next", "Segoe UI", "Noto Sans", system-ui, sans-serif;
+  
+  --shadow-soft: 0 1px 2px 0 rgb(23 32 46 / 0.06);
+  --shadow-card: 0 12px 30px -12px rgb(23 32 46 / 0.22);
 }
 
 .dark {
@@ -88,3 +91,18 @@ html {
     scroll-behavior: auto !important;
   }
 }
+
+/* Custom utilities - use directly in components */
+.shadow-soft {
+  box-shadow: var(--shadow-soft);
+}
+
+.shadow-card {
+  box-shadow: var(--shadow-card);
+}
+
+/* Dark mode overrides */
+.dark {
+  --shadow-soft: 0 1px 2px 0 rgb(2 8 18 / 0.35);
+  --shadow-card: 0 12px 30px -12px rgb(2 8 18 / 0.55);
+}