style: drop redundant comments and apply formatting

Frontend now uses double quotes and semicolons. No behaviour change.

src/App.tsx

@@ -1,13 +1,20 @@
-import { useState } from 'react'
-import { BrowserRouter, Link, Navigate, Outlet, Route, Routes } from 'react-router'
-import { errorMessage } from './api'
-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 { BookForm } from './books/BookForm'
-import { secondaryButton } from './ui'
+import { useState } from "react";
+import {
+  BrowserRouter,
+  Link,
+  Navigate,
+  Outlet,
+  Route,
+  Routes,
+} from "react-router";
+import { errorMessage } from "./api";
+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 { BookForm } from "./books/BookForm";
+import { secondaryButton } from "./ui";
 
 export function App() {
   return (
@@ -16,7 +23,7 @@ export function App() {
         <AppRoutes />
       </AuthProvider>
     </BrowserRouter>
-  )
+  );
 }
 
 export function AppRoutes() {
@@ -33,12 +40,12 @@ export function AppRoutes() {
       </Route>
       <Route path="*" element={<Navigate to="/books" replace />} />
     </Routes>
-  )
+  );
 }
 
 function Shell() {
-  const { user, logout } = useAuth()
-  const [error, setError] = useState<string | null>(null)
+  const { user, logout } = useAuth();
+  const [error, setError] = useState<string | null>(null);
   return (
     <div className="min-h-screen bg-slate-50 text-slate-900">
       <header className="border-b border-slate-200 bg-white">
@@ -51,14 +58,19 @@ function Shell() {
             <button
               type="button"
               className={secondaryButton}
-              onClick={() => logout().catch((err) => setError(errorMessage(err)))}
+              onClick={() =>
+                logout().catch((err) => setError(errorMessage(err)))
+              }
             >
               Log out
             </button>
           </div>
         </div>
         {error && (
-          <p role="alert" className="mx-auto max-w-4xl px-4 pb-2 text-sm text-red-700">
+          <p
+            role="alert"
+            className="mx-auto max-w-4xl px-4 pb-2 text-sm text-red-700"
+          >
             {error}
           </p>
         )}
@@ -67,5 +79,5 @@ function Shell() {
         <Outlet />
       </main>
     </div>
-  )
+  );
 }