fix(web): 因子研究/回测改走异步 Job（修复全市场研究长请求被代理中断 500）

- 根因：全市场因子测试同步执行约 47s，经 Next 同源代理转发时长请求被 socket 中断（前端日志：Failed to proxy .../api/factor-tests [socket hang up]）
- factors/backtest 页改为 POST /api/jobs 提交 → 轮询 GET /api/jobs/{id} → 取内嵌结果（AGENT §19 异步化）
- 新增 lib/jobs.ts（submitJob / waitJob，超时 10 分钟），运行中显示 Job 号
- 端到端验证：全市场 momentum_60 测试 JOB-93479087 → success（IC -0.0598，样本 323 日）+ Experiment 归档
- tsc + next build 通过；同步接口保留（适合小样本/脚本调用）

frontend/web/app/backtest/page.tsx

@@ -1,7 +1,8 @@
 "use client";
 
 import { useEffect, useState } from "react";
-import { apiGet, apiPost } from "@/lib/api";
+import { apiGet } from "@/lib/api";
+import { submitJob, waitJob } from "@/lib/jobs";
 import type { BacktestResult, FactorMeta, ResearchSpec } from "@/lib/types";
 import { LineChart } from "@/components/LineChart";
 
@@ -15,6 +16,7 @@ export default function BacktestPage() {
   const [excludeSt, setExcludeSt] = useState(true);
   const [result, setResult] = useState<BacktestResult | null>(null);
   const [running, setRunning] = useState(false);
+  const [jobId, setJobId] = useState("");
   const [error, setError] = useState("");
 
   useEffect(() => {
@@ -23,21 +25,34 @@ export default function BacktestPage() {
       .catch((e: Error) => setError(e.message));
   }, []);
 
-  function run() {
+  async function run() {
     setRunning(true);
     setError("");
-    const spec: ResearchSpec = {
-      type: "backtest",
-      universe: { exclude_st: excludeSt, min_listing_days: 0 },
-      factors: [{ name: factor, weight: 1 }],
-      selection: { top_n: topN },
-      rebalance,
-      period: [start, end],
-    };
-    apiPost<BacktestResult>("/backtests", spec)
-      .then(setResult)
-      .catch((e: Error) => setError(e.message))
-      .finally(() => setRunning(false));
+    setJobId("");
+    setResult(null);
+    try {
+      const spec: ResearchSpec = {
+        type: "backtest",
+        universe: { exclude_st: excludeSt, min_listing_days: 0 },
+        factors: [{ name: factor, weight: 1 }],
+        selection: { top_n: topN },
+        rebalance,
+        period: [start, end],
+      };
+      // 异步 Job：后台执行（全市场可能数十秒），轮询到终态
+      const { job_id } = await submitJob(spec);
+      setJobId(job_id);
+      const out = await waitJob<BacktestResult>(job_id);
+      if (out.status === "success" && out.result) {
+        setResult(out.result);
+      } else {
+        setError(`任务${out.status}${out.error ? `：${out.error}` : ""}`);
+      }
+    } catch (e) {
+      setError((e as Error).message);
+    } finally {
+      setRunning(false);
+    }
   }
 
   const s = result?.summary;
@@ -94,9 +109,10 @@ export default function BacktestPage() {
             剔除 ST
           </label>
           <button className="primary" onClick={run} disabled={running}>
-            {running ? "运行中…" : "运行回测"}
+            {running ? "后台运行中…" : "运行回测"}
           </button>
         </div>
+        {running && jobId && <div className="muted">任务 {jobId} 后台执行中，请稍候…</div>}
         {error && <div className="error">{error}</div>}
       </div>