feat(ui): Add pagination to books pages and improve spacing

- Added CursorPagination component with page size selector (20/50/100)
- Updated /books page with pagination support
- Updated /libraries/[id]/books with pagination
- Improved layout margins (added pb-16 and responsive px)
- Series page uses improved layout spacing

apps/backoffice/app/layout.tsx

@@ -65,7 +65,7 @@ export default function RootLayout({ children }: { children: ReactNode }) {
           </nav>
 
           {/* Main Content */}
-          <main className="container mx-auto px-4 py-8">
+          <main className="container mx-auto px-4 sm:px-6 lg:px-8 py-8 pb-16">
             {children}
           </main>
         </ThemeProvider>