fix(strategy): 编辑器代码空白根因=/strategy/files不含code; 加GET /strategy/file/{name}按需拉取; 运行回测改回跳参数页+按策略预填(New.vue读query.class,推翻上轮直接发起) [nas]

tests/api/test_routes_strategy.py

@@ -53,3 +53,17 @@ def test_file_write_rejects_syntax_error(monkeypatch, tmp_path):
     # 故意写语法错误的代码 → 400（py_compile 门禁）
     r = c.post("/api/v1/strategy/file/__probe_bad.py", json={"code": "def (:"})
     assert r.status_code == 400
+
+
+def test_file_read_returns_code(monkeypatch, tmp_path):
+    c = _client(monkeypatch, tmp_path)
+    files = c.get("/api/v1/strategy/files").json()["files"]
+    if not files:
+        return
+    name = files[0]["name"]
+    r = c.get(f"/api/v1/strategy/file/{name}")
+    assert r.status_code == 200, r.text
+    body = r.json()
+    assert isinstance(body["code"], str) and body["code"]  # 编辑器空白 bug 的回归测试
+    assert body["name"] == name
+    assert c.get("/api/v1/strategy/file/__no_such__.py").status_code == 404