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, 0 insertions, 45 deletions

diff --git a/frontend/app/routes/_index.tsx b/frontend/app/routes/_index.tsx
deleted file mode 100644
index 207b175..0000000
--- a/frontend/app/routes/_index.tsx
+++ /dev/null
@@ -1,45 +0,0 @@
-import type { LoaderFunctionArgs, MetaFunction } from "react-router";
-import { ensureUserNotLoggedIn } from "../.server/auth";
-import BorderedContainer from "../components/BorderedContainer";
-import NavigateLink from "../components/NavigateLink";
-import { APP_NAME, BASE_PATH } from "../config";
-
-export const meta: MetaFunction = () => [{ title: APP_NAME }];
-
-export async function loader({ request }: LoaderFunctionArgs) {
-	await ensureUserNotLoggedIn(request);
-	return null;
-}
-
-export default function Index() {
-	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>
-	);
-}