feat: add middlware to check auth route

frontend/middleware.ts

@@ -0,0 +1,22 @@
+import { NextResponse } from "next/server";
+import type { NextRequest } from "next/server";
+
+export function middleware(request: NextRequest) {
+  const token = request.cookies.get("token");
+  if (!token) {
+    const url = request.nextUrl.clone();
+    url.pathname = "/auth/signin";
+    return NextResponse.redirect(url);
+  }
+  return NextResponse.next();
+}
+
+export const config = {
+  matcher: [
+    // This will match all paths that:
+    // - have at least one character after "/"
+    // - do NOT start with /_next/static, /_next/image, /favicon.ico, /hub, or /auth.
+    //   (thus "/auth/signin", "/" and any "/hub" route are not processed by this middleware)
+    "/((?!_next/static|_next/image|favicon.ico|hub|auth).+)",
+  ],
+};