test+fix: 新浪 jsonp 稳健解析（容忍注释/括号包裹/尾部杂字符）；Job API 测试改 tmp 种子库

- 真实响应含 /*...*/ 注释与 var data=([...]); 前缀 → _extract_jsonp 取首 '[' 至末 ']'
- 新浪真实网络冒烟通过：财务 100 期（含披露日）+ 日K 最近窗口（source=sina/adjust=qfq）
- TestJobsApi / experiments 用例改为 monkeypatch SessionLocal → tmp 种子库（5 股×300 日），
  与真实全市场库（779 万行）解耦，全量稳定 <1min
- pytest 全量 141 passed / ruff clean

backend/tests/test_sina_provider.py

@@ -154,3 +154,18 @@ class TestFormatParity:
         # 与 Tushare 同 schema：必备字段齐全
         assert bar.symbol == "600519.SH"
         assert bar.close is not None
+
+
+class TestJsonpParens:
+    def test_real_world_paren_wrapped(self) -> None:
+        payload = 'var data=([{"day":"2024-08-30","close":"1710.0"}])'
+        rows = _extract_jsonp(payload)
+        assert rows[0]["close"] == "1710.0"
+
+    def test_with_leading_comment_and_trailing_semicolon(self) -> None:
+        payload = (
+            "/*<script>location.href='//sina.com';</script>*/\n"
+            'var data=([{"day":"2024-08-30","close":"1710.0"}]);'
+        )
+        rows = _extract_jsonp(payload)
+        assert rows[0]["close"] == "1710.0"