refactor(frontend): replace React Router BFF with Wouter SPA

Remove React Router 7 SSR/BFF architecture (server-side loaders,
actions, sessions, remix-auth) and replace with a client-side SPA
using Wouter for routing and cookie-based JWT auth.

- Replace reactRouter() Vite plugin with @vitejs/plugin-react
- Add index.html + app/main.tsx as SPA entry points
- Add Wouter routing with auth guards (ProtectedRoute/PublicOnlyRoute)
- Add client-side auth (app/auth.ts) and useAuth hook
- Migrate all route files to app/pages/ with client-side data fetching
- Update NavigateLink and GolfPlayAppGaming to use Wouter Link
- Remove .server/, routes/, root.tsx, react-router.config.ts
- Clean up tsconfig.json (remove .react-router references)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/frontend/app/pages/IndexPage.tsx b/frontend/app/pages/IndexPage.tsx
new file mode 100644
index 0000000..088cdc5
--- /dev/null
+++ b/frontend/app/pages/IndexPage.tsx
@@ -0,0 +1,39 @@
+import BorderedContainer from "../components/BorderedContainer";
+import NavigateLink from "../components/NavigateLink";
+import { APP_NAME, BASE_PATH } from "../config";
+import { usePageTitle } from "../hooks/usePageTitle";
+
+export default function IndexPage() {
+	usePageTitle(APP_NAME);
+
+	return (
+		<div className="min-h-screen bg-gray-100 flex flex-col items-center justify-center gap-y-6">
+			<img
+				src={`${BASE_PATH}logo.svg`}
+				alt="iOSDC Japan 2025"
+				className="w-96 h-auto"
+			/>
+			<div className="text-center">
+				<div className="font-bold text-transparent bg-clip-text bg-iosdc-japan">
+					<div className="text-6xl">Swift Code Battle</div>
+				</div>
+			</div>
+			<div className="mx-2">
+				<BorderedContainer>
+					<p className="text-gray-900 max-w-prose">
+						Swift コードバトルは指示された動作をする Swift
+						コードをより短く書けた方が勝ち、という 1 対 1
+						の対戦コンテンツです。9/6
+						に実施された予選を勝ち抜いたプレイヤーによるトーナメント形式での
+						コードバトルを 9/19 (金) day0
+						に実施します。ここでは短いコードが正義です！
+						可読性も保守性も放り投げた、イベントならではのコードをお楽しみください！
+					</p>
+				</BorderedContainer>
+			</div>
+			<div>
+				<NavigateLink to="/login">ログイン</NavigateLink>
+			</div>
+		</div>
+	);
+}