fix: use canonical Auth.js session in proxy

src/lib/proxy-access.ts

@@ -2,15 +2,6 @@ export interface ProxyToken {
   rank?: unknown;
 }
 
-const AUTH_COOKIE_NAMES = ["__Secure-authjs.session-token", "authjs.session-token"] as const;
-
-export function authSessionCookieName(cookieNames: readonly string[]): string | null {
-  for (const base of AUTH_COOKIE_NAMES) {
-    if (cookieNames.some((name) => name === base || name.startsWith(`${base}.`))) return base;
-  }
-  return null;
-}
-
 export function shouldRedirectAdminRequest(pathname: string, token: ProxyToken | null): boolean {
   if (pathname !== "/admin" && !pathname.startsWith("/admin/")) return false;
   return token === null;