feat: add realtime challenge client and local smoke test

backend/static/js/app.js

@@ -308,12 +308,8 @@ async function beginContest(contest) {
   if (!requireAuth()) return;
   try {
     if (contest.kind === "realtime") {
-      const match = await api(`contests/${contest.slug}/matchmaking/`, { method: "POST", body: {} });
-      if (match.status === "waiting") {
-        showToast("已进入匹配队列，等待同赛道对手");
-        return;
-      }
-      renderAttempt(match.attempt);
+      await window.HuluRealtime.startRandom(contest);
+      return;
     } else {
       renderAttempt(await api(`contests/${contest.slug}/start/`, { method: "POST", body: {} }));
     }
@@ -951,6 +947,7 @@ function bindUI() {
   $("#auth-button").addEventListener("click", async () => {
     if (!state.user) return openAuth();
     await api("accounts/logout/", { method: "POST", body: {} });
+    window.HuluRealtime?.reset();
     state.user = null;
     updateUserUI();
     showToast("已退出登录");
@@ -996,6 +993,7 @@ function bindUI() {
 async function boot() {
   bindUI();
   window.HuluToolbox?.init();
+  window.HuluRealtime?.init();
   renderSymbols();
   await Promise.all([
     loadUser(),