feat: add book detail with progress updates and delete

Claude-Session: https://claude.ai/code/session_01M9MLit5Ko3X4s7rzC5Kv7X

src/App.tsx

@@ -5,6 +5,7 @@ import { AuthProvider, useAuth } from './auth/AuthContext'
 import { LoginForm } from './auth/LoginForm'
 import { RequireAuth } from './auth/RequireAuth'
 import { BookList } from './books/BookList'
+import { BookDetail } from './books/BookDetail'
 import { secondaryButton } from './ui'
 
 export function App() {
@@ -24,6 +25,7 @@ export function AppRoutes() {
       <Route element={<RequireAuth />}>
         <Route element={<Shell />}>
           <Route path="/books" element={<BookList />} />
+          <Route path="/books/:id" element={<BookDetail />} />
         </Route>
       </Route>
       <Route path="*" element={<Navigate to="/books" replace />} />