feat(deck): separate card list from deck detail page

Separate the card list view from the deck learning page to prevent users
from seeing cards they are about to study. The deck detail page now shows
only study statistics with a "Study Now" button and a "View Cards" link.

- Add new DeckCardsPage component at /decks/:deckId/cards for managing cards
- Simplify DeckDetailPage to show deck stats and navigation buttons
- Update routing in App.tsx with proper route ordering
- Add comprehensive tests for both pages

1 files changed, 8 insertions, 2 deletions

diff --git a/src/client/App.tsx b/src/client/App.tsx
index e1b794c..69af60f 100644
--- a/src/client/App.tsx
+++ b/src/client/App.tsx
@@ -1,6 +1,7 @@
 import { Route, Switch } from "wouter";
 import { OfflineBanner, ProtectedRoute } from "./components";
 import {
+	DeckCardsPage,
 	DeckDetailPage,
 	HomePage,
 	LoginPage,
@@ -19,9 +20,9 @@ export function App() {
 						<HomePage />
 					</ProtectedRoute>
 				</Route>
-				<Route path="/decks/:deckId">
+				<Route path="/decks/:deckId/cards">
 					<ProtectedRoute>
-						<DeckDetailPage />
+						<DeckCardsPage />
 					</ProtectedRoute>
 				</Route>
 				<Route path="/decks/:deckId/study">
@@ -29,6 +30,11 @@ export function App() {
 						<StudyPage />
 					</ProtectedRoute>
 				</Route>
+				<Route path="/decks/:deckId">
+					<ProtectedRoute>
+						<DeckDetailPage />
+					</ProtectedRoute>
+				</Route>
 				<Route path="/note-types">
 					<ProtectedRoute>
 						<NoteTypesPage />