切换演示数据到 demo 目录

- 默认演示视频和 DICOM 路径改为 demo/演视LC视频序列.mp4 与 demo/演视DICOM序列/。

- 演示 DICOM 项目名统一为“演视DICOM序列”，并兼容迁移旧“演示DICOM序列”名称。

- 恢复演示出厂设置测试改为验证新文件名上传路径和新项目名。

- 同步更新用户管理提示、API 契约、安装文档、实现地图和项目指南。

- 本地与 ../Seg_Server_Docker 已实际放入 demo 演示视频和 DICOM 测试影像；数据文件受 .gitignore 保护不进入提交。

backend/tests/test_admin.py

@@ -118,7 +118,7 @@ def test_admin_cannot_delete_self_but_can_delete_project_author(client, db_sessi
 
 
 def test_demo_factory_reset_leaves_admin_and_parsed_demo_dicom(client, db_session, monkeypatch, tmp_path):
-    video_path = tmp_path / "Data_MyVideo_1.mp4"
+    video_path = tmp_path / "演视LC视频序列.mp4"
     video_path.write_bytes(b"demo-video")
     monkeypatch.setattr("routers.admin.settings.demo_video_path", str(video_path))
     dicom_dir = tmp_path / "dicom"
@@ -189,12 +189,12 @@ def test_demo_factory_reset_leaves_admin_and_parsed_demo_dicom(client, db_sessio
     data = response.json()
     assert data["message"] == "演示环境已恢复出厂设置"
     assert data["admin_user"]["username"] == "admin"
-    assert data["project"]["name"] == "演示DICOM序列"
+    assert data["project"]["name"] == "演视DICOM序列"
     assert data["project"]["status"] == PROJECT_STATUS_READY
     assert data["project"]["source_type"] == "dicom"
     assert data["project"]["frame_count"] == 3
     assert data["project"]["video_path"] == f"uploads/{data['project']['id']}/dicom"
-    assert [project["name"] for project in data["projects"]] == ["演视LC视频序列", "演示DICOM序列"]
+    assert [project["name"] for project in data["projects"]] == ["演视LC视频序列", "演视DICOM序列"]
     assert data["projects"][0]["status"] == "pending"
     assert data["projects"][0]["source_type"] == "video"
     assert data["projects"][0]["frame_count"] == 0
@@ -202,7 +202,7 @@ def test_demo_factory_reset_leaves_admin_and_parsed_demo_dicom(client, db_sessio
     assert data["projects"][1]["source_type"] == "dicom"
     assert data["projects"][1]["frame_count"] == 3
     assert [item["object_name"] for item in uploaded] == [
-        f"uploads/{data['projects'][0]['id']}/Data_MyVideo_1.mp4",
+        f"uploads/{data['projects'][0]['id']}/演视LC视频序列.mp4",
         f"uploads/{data['project']['id']}/dicom/1.dcm",
         f"uploads/{data['project']['id']}/dicom/2.dcm",
         f"uploads/{data['project']['id']}/dicom/10.dcm",