调整项目库拆帧与长帧序列加载

- 删除项目库右上角独立新建项目入口，保留导入视频/DICOM 自动建项目流程

- 视频项目支持已生成帧后的重新生成帧入口，并提示会清空旧帧、标注和 mask

- 后端重新拆帧任务开始前清理旧帧、旧标注和旧 mask，避免重复帧序列

- 项目帧列表接口默认返回完整帧序列，避免工作区总帧数被 1000 条默认 limit 截断

- 增加可选 docker-compose.gpu.yml，并补充 Docker 使用本机 GPU 的前提和启动说明

- 更新项目库、API 映射、恢复演示文案、后端媒体/项目测试和前端文档

backend/tests/test_media.py

@@ -216,6 +216,60 @@ def test_parse_task_runner_registers_frames(client, db_session, monkeypatch, tmp
     assert frames[0]["source_frame_number"] == 0
 
 
+def test_parse_task_runner_replaces_existing_frames_and_annotations(client, db_session, monkeypatch, tmp_path):
+    from models import Annotation, Frame, Mask, ProcessingTask
+    from services.media_task_runner import run_parse_media_task
+
+    project = client.post("/api/projects", json={
+        "name": "Reparse Me",
+        "video_path": "uploads/1/clip.mp4",
+        "source_type": "video",
+        "status": "ready",
+        "parse_fps": 30,
+        "thumbnail_url": "projects/old/thumbnail.jpg",
+    }).json()
+    old_frame = Frame(project_id=project["id"], frame_index=0, image_url="projects/old/frame.jpg")
+    db_session.add(old_frame)
+    db_session.commit()
+    db_session.refresh(old_frame)
+    old_annotation = Annotation(project_id=project["id"], frame_id=old_frame.id, mask_data={"label": "old"})
+    db_session.add(old_annotation)
+    db_session.commit()
+    db_session.refresh(old_annotation)
+    db_session.add(Mask(annotation_id=old_annotation.id, mask_url="masks/old.png"))
+    task = ProcessingTask(
+        task_type="parse_video",
+        status="queued",
+        progress=0,
+        project_id=project["id"],
+        payload={"source_type": "video", "parse_fps": 10},
+    )
+    db_session.add(task)
+    db_session.commit()
+    db_session.refresh(task)
+
+    frame_file = tmp_path / "frame_000000.jpg"
+    frame_file.write_bytes(b"new frame")
+    monkeypatch.setattr("services.media_task_runner.download_file", lambda object_name: b"video")
+    monkeypatch.setattr(
+        "services.media_task_runner.parse_video",
+        lambda local_path, output_dir, fps, max_frames=None, target_width=640: ([str(frame_file)], 25.0),
+    )
+    monkeypatch.setattr("services.media_task_runner.extract_thumbnail", lambda local_path, thumbnail_path: open(thumbnail_path, "wb").write(b"thumb"))
+    monkeypatch.setattr("services.media_task_runner.upload_file", lambda *args, **kwargs: None)
+    monkeypatch.setattr("services.media_task_runner.upload_frames_to_minio", lambda frame_files, project_id: [f"projects/{project_id}/frames/frame_000000.jpg"])
+    monkeypatch.setattr("services.media_task_runner.publish_task_progress_event", lambda task: None)
+
+    result = run_parse_media_task(db_session, task.id)
+
+    assert result["frames_extracted"] == 1
+    frames = db_session.query(Frame).filter(Frame.project_id == project["id"]).all()
+    assert len(frames) == 1
+    assert frames[0].image_url == f"projects/{project['id']}/frames/frame_000000.jpg"
+    assert db_session.query(Annotation).filter(Annotation.project_id == project["id"]).count() == 0
+    assert db_session.query(Mask).count() == 0
+
+
 def test_parse_dicom_reads_files_in_natural_filename_order(monkeypatch, tmp_path):
     from pathlib import Path
 

backend/tests/test_projects.py

@@ -50,6 +50,29 @@ def test_project_crud_and_frames(client, monkeypatch):
     assert client.get(f"/api/projects/{project_id}").status_code == 404
 
 
+def test_list_project_frames_returns_more_than_default_timeline_window(client, db_session, monkeypatch):
+    monkeypatch.setattr("routers.projects.get_presigned_url", lambda key, expires=3600: f"http://storage/{key}")
+    created = client.post("/api/projects", json={"name": "Long Sequence", "status": "ready"})
+    assert created.status_code == 201
+    project_id = created.json()["id"]
+
+    db_session.add_all([
+        Frame(project_id=project_id, frame_index=index, image_url=f"frames/{index}.jpg")
+        for index in range(1001)
+    ])
+    db_session.commit()
+
+    frames = client.get(f"/api/projects/{project_id}/frames")
+    assert frames.status_code == 200
+    body = frames.json()
+    assert len(body) == 1001
+    assert body[-1]["frame_index"] == 1000
+
+    limited = client.get(f"/api/projects/{project_id}/frames?limit=2")
+    assert limited.status_code == 200
+    assert [frame["frame_index"] for frame in limited.json()] == [0, 1]
+
+
 def test_delete_project_cascades_related_records(client, db_session):
     created = client.post("/api/projects", json={"name": "Cascade Delete"})
     assert created.status_code == 201