feat: Phase 4 — Experiment 自动归档 + 异步 Job（状态机 / SSE / 一键复跑）

- 数据表：job / experiment（spec/result JSON 存档、code_version），Alembic 迁移 53113c80257f
- Job：queued→running→(success|failed) 状态机，BackgroundTasks 本地执行 + 失败兜底标记；结果与 Experiment 关联
- Experiment：每次研究成功自动归档（含 git commit 与收益摘要），支持一键复跑（同 spec 重建 Job）
- API：POST /api/jobs、GET /api/jobs/{id}（内嵌结果）、SSE /api/jobs/{id}/events、/api/experiments 列表/详情/rerun
- 前端：新增「实验」页（列表 / 详情 / 复跑 + Job 轮询）；导航更新
- 端到端验证：真实 20 股 job 提交→后台执行→success→EXP 归档（-12.41%）；executor 成功/失败路径单测
- 测试 73 passed（新增 5 项 Job/Experiment）/ ruff clean / 前端 tsc + build 通过

backend/app/api/jobs.py

@@ -0,0 +1,110 @@
+"""异步研究 Job API（Phase 4）：提交 / 查询 / SSE 进度。
+
+POST /api/jobs          创建 Job（BackgroundTasks 本地执行），立即返回 job_id
+GET  /api/jobs/{id}     状态 + 结果（成功时内嵌 result）
+GET  /api/jobs/{id}/events  SSE 进度（queued→running→success|failed）
+"""
+
+from __future__ import annotations
+
+import asyncio
+import json
+from datetime import datetime
+
+from fastapi import APIRouter, BackgroundTasks, HTTPException
+from fastapi.responses import StreamingResponse
+
+from app.api.deps import DbSession, JobRepoDep, _engine_factory
+from app.application.services.job_executor import execute_job, new_id
+from app.domain.entities.research import (
+    BacktestResult,
+    FactorTestReport,
+    JobRecord,
+    JobStatus,
+    ResearchSpec,
+)
+from app.infrastructure.persistence.sqlalchemy.repositories.jobs_impl import (
+    SqlAlchemyExperimentRepository,
+    SqlAlchemyJobRepository,
+)
+from app.infrastructure.persistence.sqlalchemy.repositories.market_impl import (
+    SqlAlchemyDailyBarRepository,
+    SqlAlchemyStockRepository,
+)
+from app.infrastructure.persistence.sqlalchemy.session import SessionLocal
+
+router = APIRouter(prefix="/jobs", tags=["jobs"])
+
+
+def _bg_factories():
+    return {
+        "session_factory": SessionLocal,
+        "job_repo_factory": lambda s: SqlAlchemyJobRepository(s),
+        "experiment_repo_factory": lambda s: SqlAlchemyExperimentRepository(s),
+        "stock_repo_factory": lambda s: SqlAlchemyStockRepository(s),
+        "daily_repo_factory": lambda s: SqlAlchemyDailyBarRepository(s),
+        "engine": _engine_factory(),
+    }
+
+
+def _decode_result(kind: str, result_json: str | None):
+    if result_json is None:
+        return None
+    model = BacktestResult if kind == "backtest" else FactorTestReport
+    return model.model_validate_json(result_json)
+
+
+def _job_view(job: JobRecord) -> dict:
+    view = job.model_dump()
+    view["result"] = _decode_result(job.kind, job.result_json)
+    view.pop("result_json", None)
+    view["spec"] = json.loads(job.spec_json)
+    return view
+
+
+@router.post("", summary="创建异步研究 Job")
+def create_job(
+    spec: ResearchSpec,
+    background: BackgroundTasks,
+    session: DbSession,
+    job_repo: JobRepoDep,
+) -> dict:
+    job = JobRecord(
+        id=new_id("JOB"),
+        kind=spec.type,
+        spec_json=spec.model_dump_json(),
+        status=JobStatus.QUEUED,
+        created_at=datetime.now(),
+    )
+    job_repo.create(job)
+    session.commit()
+    background.add_task(execute_job, job.id, **_bg_factories())
+    return {"job_id": job.id, "status": job.status}
+
+
+@router.get("/{job_id}", summary="查询 Job 状态与结果")
+def get_job(job_id: str, job_repo: JobRepoDep) -> dict:
+    job = job_repo.get(job_id)
+    if job is None:
+        raise HTTPException(status_code=404, detail=f"Job {job_id} 不存在")
+    return _job_view(job)
+
+
+@router.get("/{job_id}/events", summary="Job 进度 SSE")
+async def job_events(job_id: str) -> StreamingResponse:
+    async def gen():
+        while True:
+            with SessionLocal() as session:
+                job = SqlAlchemyJobRepository(session).get(job_id)
+            if job is None:
+                yield "event: error\ndata: job not found\n\n"
+                return
+            payload = json.dumps(
+                {"job_id": job.id, "status": job.status, "stage": job.stage}, ensure_ascii=False
+            )
+            yield f"data: {payload}\n\n"
+            if job.status in (JobStatus.SUCCESS, JobStatus.FAILED, JobStatus.CANCELLED):
+                return
+            await asyncio.sleep(0.4)
+
+    return StreamingResponse(gen(), media_type="text/event-stream")